The Treasure of Gold and Silver Artifacts from Royal Tombs of Sipán, Peru. Hörz & Kallffass

The treasure of gold and silver artifacts from the Royal

Tombs of SipaÂn, Peru Ð a study on the Moche

metalworking techniques

G. HoÈrz*, M. Kallfass

Max-Planck-Institut fuÈr Metallforschung, Seestrasse 92, Stuttgart D-70174, Germany

Received 3 May 2000; accepted 20 August 2000

Abstract

In 1987±1990, a spectacular treasure of gold and silver ornamental and ceremonial artifacts was recovered

scientifically from the unlooted Royal Tombs of SipaÂn, Peru (dated to approximately AD 50±300). These objects

give evidence of the outstanding craftsmanship of the Moche metalsmiths and reflect the various elaborate

metalworking techniques available at that time. The present paper summarizes the results of a study on an array of

artifacts stemming mainly from the tomb of the `̀ Lord of SipaÂn.'' Most of the objects were found to be made of

thin sheet metal (1± < 0.1 mm thick), which was further worked by cutting, embossing, punching, and chasing.

Three-dimensional structures were created from pieces of the sheet metal by mechanical or metallurgical joining

(soldering or welding). The Moche metalsmiths were masters in making objects that looked like pure gold or

silver. In the case of copper objects, the surfaces were often found to be gilded electrochemically by the deposition

of very thin gold films. In the case of objects made of alloys of copper with gold and some silver (tumbaga) or of

copper with silver, the surface gilding or silvering was achieved by the depletion of copper, mostly by selectively

oxidizing the surface copper and etching away the copper oxides that are formed. D 2001 Elsevier Science Inc. All

rights reserved.

Keywords: Archaectechnology; Pre-Columbian metallurgy; Ancient Peruvian metallurgy; Moche metallurgy; Royal tombs of

SipaÂn, Peru; Sheet technique

1. Introduction

Long before the Inca Empire was established,

remarkable cultures and advanced civilizations rose,

flourished, and fell in the Central Andean region,

roughly corresponding to today's Peru. On the north

coast of Peru, after the period of ChavõÂn influence

(1000±200 BC), the cultures of the Moche (AD 0±

700), SicaÂn (AD 700±1375), and ChimuÂ (AD 900±

1440) followed in sequence before the Inca Empire

arose at about 1440. It ended only a hundred years

later with the arrival of the Spaniards at 1533. It

should be emphasized that the Inca Empire drew

extensively on the achievements of the preceding

Andean cultures. In particular, the Inca could profit

by the techniques based on the age-old Central

Andean metalworking tradition. After the conquest

of the ChimuÂ realm, the Inca adopted the artistic

and technical skill of the ChimuÂ metalsmiths by

bringing them to their capital, Cuzco. A series of

comprehensive well-written treatises has been pub-

1044-5803/00/$ ± see front matter D 2001 Elsevier Science Inc. All rights reserved.

PII: S1 0 4 4 - 5 8 0 3 ( 0 0 ) 0 0 0 9 3 - 0

* Corresponding author. Tel.: +49-7022-35103; fax:

+49-711-2095-215.

E-mail address: [email protected]

(M. Kallfass).

Materials Characterization 45 (2000) 391± 420

lished on the various aspects of the pre-Columbian

cultures [1±12].

One of the most remarkable civilizations, pre-

ceding the Inca Empire in ancient Peru, was that of

the Moche (for general reading, see Refs. [2,4,6±

8,11,13±17]). The Moche culture evolved in the

oasis river valleys on the arid north coast of Peru

(Fig. 1). This was around AD 50 when the Roman

Empire was approaching full expanse. Several hun-

dred years later, the cultural influence of the Moche

extended along the coastal plane some 600 km from

north to south between the valleys of the Piura

River and the Huarmey River. Due to the geo-

graphic and climatic conditions, the east-to-west

expansion was, on average, only 80 km. The sub-

sistence of the Moche was based primarily on

agriculture in the river valleys. The establishing of

a complex widespread network of irrigation canals

allowed the cultivation of a large variety of crops.

Additional food was supplied by fishing along the

coast and the rivers and, to a lesser extent, by

hunting. The meat of domesticated animals supple-

mented the Moche diet [14±17].

The Moche society apparently was highly strati-

fied and strictly organized with a high degree of

specialization of labor. It was ruled by an elite of

mighty priests, warriors, and statutory authorities.

Many workers were devoted to the construction and

maintenance of irrigational canal systems, roads,

pyramids, palaces, and temples. The most spectacular

and best-known structures were the Pyramids of the

Sun and of the Moon. As signs of the religious and

political might of Moche rulers, these pyramids were

built in the ceremonial center of the Moche in the

Moche River Valley near today's town Trujillo (Fig.

1). The Pyramid of the Sun (Huaca del Sol) once

contained more than 140 million mold-made and air-

dried adobe bricks and was about 60 m high. At the

Fig. 1. Map of the northern coast and highlands of today's Peru showing river valleys, archaeological sites, and present towns.

G. HoÈrz, M. Kallfass / Materials Characterization 45 (2000) 391±420392

time, it was the largest structure built in South

America [15±17].

The crafts of pottery, metalworking, and weaving

were highly developed in the Moche society. The

Moche potters were masters in producing bottles with

stirrup spouts and jars in clay as three-dimensional

sculptures. Moreover, the Moche craftsmen produced

clay jars and bottles in the form of heads that

exhibited individual facial features (portrait vessels).

In particular, the Moche potters were skilled at

decorating ceramic vessels with low-relief designs.

They developed a technique of painting complex

scenes on ceramic vessels that might be compared

to the method employed by the Greek vase painters of

ancient Athens. Such painted clay vessels counted to

the very best art that remained from past Indian

cultures. The presentations offered by the Moche

pottery, both painted and modeled, feature such

objects as men, women, animals, plants, anthro-

morphic demons, and deities engaged in a broad

spectrum of activities including hunting, fishing,

combat, punishment, sexual acts, and elaborate cere-

monies. Much of the pottery art seems to give insight

into the daily life of the Moche as well as religious

ceremonies, thus apparently offering us a vivid record

of some aspects of the Moche culture and society.

However, it is astonishing that many everyday activ-

ities, such as farming, cooking, and pottery making,

are never shown. According to the extensive studies

of Donnan and his scholars on the basis of a photo-

graphic archive of Moche art containing more than

125,000 photographs [16], scenes are often not what

they seem to be but are religious rituals or acts rich in

symbolism. On the other hand, the recent finds

stemming from the Royal Tombs of SipaÂn and from

the tomb of a priestess at San JoseÂ de Moro in the

lower Jequetepeque Valley [73] give solid evidence

that the so-called Sacrifice Ceremony often depicted

in Moche art had actually taken place and the most

important participants had really lived [4,10,11,14±

19,73].

The early introduction of molds and stamps made

the production of ceramics more efficient and allowed

the manufacture of many duplicates of individual

pieces. As a consequence, elaborate ceramics became

available for a wide range of Moche people and were

no longer effective for demonstrating political power,

wealth, and social status. In contrast, metal objects

made of `̀ gold'' and `̀ silver'' were high-status items

and were reserved for the elite [15,16].

Moche metalworking was based primarily upon

objects made of hammered sheet metal. The shaping

of metals and alloys by hammering and subsequent

embossing rather than by casting follows a tradition

that began at the north coast of Peru several centuries

earlier during the period of ChavõÂn influence. The

working of gold in ancient Peru, however, may be

traced back one millenium more to the south-central

highlands of Peru. At the Waywaca site, near the

modern town of Andahuaylas, numerous tiny bits of

hammered thin gold foil have been found by Gross-

man [20] in the burial of a young man and in an

adjacent refuse deposit. In addition, a metalworkers'

tool kit consisting of an anvil and three small ham-

mers made of stone was detected near this site. This

was the earliest documented evidence of metalwork-

ing in the Central Andes, dated to about 1500 BC.

Another two remarkable groups of real goldwork

were discovered at the north coast of Peru near

Chongoyape, in the Lambayeque Valley (Fig. 1), as

described by Lothrop [21]. The artifacts, mostly

ornamental objects, were crafted from hammered

sheet gold. They were of ChavõÂn style and were

dated to the middle of the first millennium BC.

Lothrop [22] depicts a third group of objects, con-

sidered to be in the ChavõÂn style. These artifacts were

made from sheets of hammered gold alloys that

contained silver and some copper. Inspecting the

artifacts in these three groups of gold work, it is

concluded that by the end of the ChavõÂn influence,

precious metal objects were manufactured by apply-

ing the sheet metal technique and the methods of

joining pieces of preshaped metal sheet by soldering

and welding. Besides native gold and native gold±

silver alloys (with some copper), probably gold and

silver were already intentionally alloyed at that time.

ChavõÂn-style artifacts, as described by Lothrop

[21,22], may be considered the earliest works of art

in gold from the Americas [23,24], marking the

visible beginning of the Central Andean tradition in

metalworking. Strikingly, the basic features of this

tradition determined the manufacture of objects in the

Andean area throughout a period of about two

millennia. This period involved the cultures of Cha-

võÂn, Moche, SicaÂn, and ChimuÂ. In Columbia, it

should be noted, the conceptually different tradition

of metalworking by lost-wax casting evolved at the

end of the first millennium BC [23].

Within the Central Andean metalworking tradi-

tion, the Moche metalsmiths were the most sophisti-

cated artisans. Continuing the tradition of the ChavõÂn

smiths, they developed alloys of copper with silver or

with gold and some silver (tumbaga). They used these

alloys in a wide range of compositions to produce

hammered sheet metal to serve as raw material for the

manufacture of objects. Especially, they used the

property of these alloys to develop silver- or gold-

looking surfaces by depleting the surface of copper.

Moreover, they invented the ingenious technique of

electrochemical deposition of thin silver or gold films

onto a copper surface. The techniques developed and

practiced by the Moche smiths were widely adopted

G. HoÈrz, M. Kallfass / Materials Characterization 45 (2000) 391±420 393

by the SicaÂn and the ChimuÂ metalworkers. However,

the virtuosity of the Moche smiths and the quality of

their products were unequaled by any of the succeed-

ing cultures, including that of the Inca (AD 1440±

1533) [29]. Information on metalworking in ancient

Peru, in particular at the time of the Moche, can be

found in Refs. [5,9,11,13,15,16,24±34,71,72].

The outstanding craftsmanship of the Moche has

been impressively demonstrated by the vast treasure

of spectacular `̀ gold'' and `̀ silver'' ornamental and

ceremonial artifacts found recently in the Royal

Tombs of SipaÂn. These unlooted tombs were discov-

ered in the ruins of an adobe pyramid, the Huaca

Rajada, near the small village of SipaÂn in the central

part of the Lambayeque River Valley (339 km from

Chiclayo) at the north coast of Peru (Fig. 1) [35±44].

The tombs were excavated during 1987±1990 under

the scientific direction of Walter Alva, director of the

BruÈning Museum (Museo ArqueoloÂgico Bruning) in

Lambayeque. Prior to the discovery of the Royal

Tombs of SipaÂn, most of the precious metal artifacts

attributed to the Moche culture came from grave

looting that was widespread. These objects were

presented as individual works of art in many museums

and private collections and, thus, were without any

reliable geographical and cultural context.

The first royal tomb discovered was that of a 35-

year-old Moche ruler and warrior priest; it is referred

to as the tomb of the `̀ Lord of SipaÂn'' (Tumba del

SenÄor de SipaÂn). The grave has been dated to about

AD 300. The large burial chamber, extending over an

area of 3.25� 2.40 m2 and having a height of almost 1

m, was originally covered with a log ceiling and was

sealed with adobe bricks. The body of the deceased

Lord laid in an elaborate coffin of wooden planks held

together by copper straps and containing rich metallic

ornaments, golden jewelry, and emblems of his worth

and power, which probably signified his triple role as

a ruler, a high priest, and a warlord. Of particular

interest is the discovery that three young women and

two men, who apparently were members of the `̀ royal

court'' of the ruler, were buried in the same chamber

[35±37,39±44].

The two other excavated Royal Tombs of SipaÂn are

designated as the tomb of the `̀ Priest'' (La Tumba del

Sacredote), which is contemporary with the tomb of

the `̀ Lord of SipaÂn,'' and the tomb of the `̀ Old Lord

of SipaÂn'' (La Tumba del Viejo SenÄor), which dates to

the earliest construction phase of the adobe pyramid

Huaca Rajada (AD 50). These tombs also contained a

large number of valuable `̀ gold'' and `̀ silver'' orna-

mental and ceremonial objects. However, they were

not as richly and splendidly endowed as the Lord's

[40,42±44]. Thus, the tomb of the `̀ Lord of SipaÂn''

can be considered to be one of the richest and most

important unlooted burial sites of the pre-Inca period

ever found and archaeologically excavated in the New

World [35±40]. In addition to about 200 ceramic

vessels and a series of utilitarian copper objects, many

valuable metallic burial gifts were recovered, the

greater part being `̀ gold'' and `̀ silver'' ornamental

and ceremonial artifacts (e.g., banners; headdresses;

eye, nose, and chin ornaments; earspools; necklaces;

ceremonial knives; backflaps; and bells). Only those

items that were made of copper±gold (±silver) alloys

and contained a high level of gold in the near-surface

Table 1

Investigated objects from the tomb of the `̀ Lord of SipaÂn'': materials and techniques of manufacture

Materials Objects Techniques

Cu Coffin straps

Spacer bars Working

Handle of a fan

Head of a spear Casting

Cu± As Rattle pellet Casting and working

Cu (Au) Banner with ornamental

platelets

Working and electrochemical

gilding

Cu± Ag `̀ Silver'' ingot Casting

Human-head beads Working, embossing,

Spacer tubings depletion silvering,

Peanut beads and metallurgical joining

Ceremonial knife Casting and working

Cu± Au ±Ag `̀ Gold'' ingot Casting

headdress Working,

Chin ornament embossing,

Ornamental disc depletion gilding,

Ornamental beads and sweat welding

}

}

}


layer retained their luster during the nearly 1700-year-

long burial in the adobe pyramid. Other items with

high copper content, especially those made of cop-

per±silver alloys and gilded copper, were covered

with green-colored crusts containing copper corrosion

products, or had corroded through and disintegrated

into fragments.

The artifacts found in the tomb of the `̀ Lord of

SipaÂn'' are of outstanding value for several reasons.

They date from approximately AD 300; at that time,

the Moche culture flourished at the north coast of

today's Peru and the metallurgical and metalworking

techniques were highly developed. Because the

objects recovered were attributed to a Moche ruler

and warrior priest, they were undoubtedly high-status

items and, therefore, reflective of the most skillful and

sophisticated manufacturing methods of the period.

Additionally, the objects were found as an ensemble

in context to not only each other but the buried ruler.

Thus, the copper, silver, and gold objects offered a

unique opportunity to study the state of the art of the

elaborate metalworking techniques at the time of the

Moche. Realization of this project was made possible

by the support of the RoÈmisch-Germanisches Zen-

tralmuseum (RGZ), Mainz, that was entrusted with

the conservation, restoration, and reconstruction of a

large part of the finds [37,45,59]. For our extensive

investigations, RGZ supplied the Max-Planck-Institut

fuÈ r Metallforschung, Stuttgart, with samples of

objects stemming preferentially from the tomb of

the `̀ Lord of SipaÂn.'' In the present paper, results on

parts of this study are reported and discussed follow-

ing the classification of objects according to Table 1.

2. Experimental methods

The samples used in this study comprised of

remains or fragments of disintegrated objects, small

pieces of material that broke off items during restora-

tion, and tiny quantities of material that could be

removed from hidden areas of selected artifacts. The

samples were defined by their origin, i.e., they could

be attributed to the specific object and often to the

part or area of the object. In the case of precious

artifacts, due to the condition of preserving them, the

free choice of sampling from points of interest was

restricted. Therefore, the reliability of the results

obtained from the examination of small isolated areas

was improved and supported by many other observa-

tions referring to the whole object. Besides the

appearance of the artifacts in the state after excava-

tion and the observations and experiences of the

restorers during reconstruction and restoration, the

close visual examination of the finds and samples by

the authors of the present work should be mentioned.

The investigated objects were made of copper, of

copper with small amounts of arsenic, and of copper

alloyed with silver or with gold and silver. Those

materials containing considerable amounts of copper

were at least partially corroded and, thus, were fre-

quently brittle. Moreover, the samples were valuable,

unique, and irreplaceable. Therefore, particularly strin-

gent requirements had to be met on their investigation.

Nevertheless, in general, standard methods of sample

preparation (mounting, grinding, and polishing) and

etching could be applied [45±47]. Modifications of the

methods, however, were necessary in the case of

samples exhibiting a composite deformed structure

containing various metallic phases and corrosion pro-

ducts. Some optimized procedures used in etching the

samples have been described in a previous work [45].

The microstructural examination of the materials

was carried out on samples in the polished or etched

condition, initially with the light microscope under

bright field illumination or with polarized light, and

subsequently mostly at higher magnification with the

scanning electron microscope. Using appropriate

methods of etching the residual metallic core of the

samples [45,47], it was possible to obtain information

about the metallurgical and metalworking prehistory

of the materials, e.g., regarding cast conditions,

segregation, deformation, and annealing treatments.

To reveal the species of corrosion of copper-con-

taining artifacts, observation of the microstructure with

polarized light proved helpful because several of the

corrosion products of copper appear in characteristic

colors. Examples are brownish-red cuprite (Cu2O) and

green malachite (CuCO3�Cu(OH)2). It should, how-

ever, be considered that a greenish color can be also an

indication of other copper corrosion products contain-

ing chlorine or sulfur (atacamite and paratacamite,

CuCl2�3Cu(OH)2 or brochantite, CuSO4�3Cu(OH)2).

To differentiate between the green-colored species,

phase analyses using X-ray diffraction by the Guinier

method using CuKa1 radiation [48,49] and electron

beam microanalysis [50,51] must be carried out. How-

ever, X-ray diffraction cannot differentiate between

atacamite and paratacamite, which are polymorphous

modifications of the basic copper chloride

(CuCl2�3Cu(OH)2). When copper-containing artifacts

are buried in soil over long archaeological periods of

time, the basic copper chloride appears often to be in

the paratacamite form [45]. Therefore, and for simpli-

city, in the following text, only the paratacamite

modification together with the possibly present mala-

chite will be referred to. The most important corrosion

products of copper, together with details of their

chemical composition, copper content, lattice struc-

ture, and color, are summarized in Refs. [45,52].

In determining the integral chemical composition

of the samples, analyses were made wherever possi-


ble of both the remaining metallic regions and the

corroded areas of the samples. Semiquantitative com-

position data were obtained from X-ray fluorescence

analysis (XRFA), while more sensitive quantitative

analyses were made by optical emission spectrometry

with inductively coupled, high-frequency plasma (ICP-

OES) using a polychromator and argon plasma [53,54].

Local element concentrations of small areas of the

sample surface were measured by electron beam

microanalysis. In this technique, the intensities of

characteristic X-rays excited by the electron beam

are measured and analyzed either according to their

respective energies (energy-dispersive spectrometry,

EDS) or wavelengths (wavelength-dispersive spectro-

metry, WDS) [50,51]. At optimum resolution, the

information obtained by WDS is characteristic of a

sample volume with a surface of 1±2 mm in diameter

and a depth of 1±2 mm. It is, thus, possible to analyze

the distribution of elements in the sample surface or

across a section point-by-point at a distance of 1±2

mm from one another. This type of WDS line scan

analysis was carried out on samples exhibiting seg-

regation or various alternately occurring phases.

For the compositional analysis of the near-surface

regions of gilded or silvered artifacts, Auger electron

spectroscopy (AES), in combination with argon ion

sputtering, was a suitable method [55,56]. By mea-

suring the depth profiles of element distribution,

information on changes in the element concentration

to a depth of about 5 mm was obtained [57].

3. Fundamental results

The objects of the tomb of the Lord of SipaÂn

studied in this work are, in particular, ornamental and

ceremonial artifacts exhibiting, after their restoration,

a gold or silver appearance. Most of the items were

found to be made of hammered thin sheet metal of

uniform thickness between about 1 and < 0.1 mm,

while only few objects were manufactured by casting.

Many objects were crafted in parts by embossing and

then joined together along their edges to create three-

dimensional structures. Examples of both mechanical

joining (crimping, stapling, and tab-and-slot techni-

que) and metallurgical joining (soldering and weld-

ing) were detected and studied.

The greater part of the investigated objects was

made of alloys (Table 1) exhibiting various combina-

tions and concentrations of copper, gold, and silver

(Table 2). The bulk compositions of some `̀ gold''

artifacts are marked in the ternary gold±silver±cop-

per phase diagram [61] in Fig. 2 by the points 2±7.

Of special interest was the finding of three ingots

looking like gold and one ingot that was originally

covered with copper corrosion products and had, after

cleaning (by treating the object with a reducing, low-

pressure hydrogen plasma [58]), a grey-silvery

appearance. One of the `̀ gold'' ingots was found on

top of a decomposed headdress and another one was

found in the mouth of the diseased Lord. The third

`̀ gold'' ingot was lying on the Lord's right hand,

whereas the `̀ silver'' ingot was lying on his left hand

[40]. This pairing of gold and silver (here linked with

pairing of right and left sides) obviously was a

common practice in the Moche culture and presum-

ably had a symbolic meaning to the Moche [40,60].

Among the artifacts stemming from the royal tombs,

some more examples expressing the gold ± silver

duality were detected [40].

Compositional analyses data (Table 2) show that

the `̀ silver'' ingot contains only 28.8% Ag, while one

Table 2

Chemical composition of some objects from the tomb of the `̀ Lord of SipaÂn'' (concentrations are for the bulk material and are

given as weight percent)

Object Numbera Method Cu % Au % Ag %

`̀ Silver'' ingot ICP-OESb 66.9 1.3 28.8

`̀ Gold'' ingot 1 ICP-OESb 39.0 48.4 12.7

Ornamental disc 4 ICP-OESb 21.6 61.2 17.0

Ornamental bead 6 ICP-OESb 21.9 53.7 18.7

Ornamental bead 5 WDSc 23.5 58.6 17.9

Ornamental bead 7 WDSc 46.5 45.0 8.5

Chin ornament 2 WDSc 54.5 35.6 11.1

Headdress 3 WDSc + ICP-OESb 60 34 6

Human-head bead Structural analysisd 79 1 20

Peanut bead Structural analysisd 15 ± 85

Ceremonial knife Structural analysisd 50 ± 50

a Numbers refer to the notation in the ternary Ag ±Au ±Cu diagram in Fig. 2.b ICP-OES analyses are based on sufficient quantities of material.c WDS analyses are restricted to small isolated material areas; data are of less reliability.d Estimated values on the basis of the structural distribution of Cu-rich and Ag-rich phases are less reliable.


of the `̀ gold'' ingots has a gold content of 48.4%.

These ingots have the shape of an inverse flat cone,

the height amounting to 16.5 or 11.5 mm, respec-

tively, and the diameter at the upper surface amount-

ing to about 47 mm for both items (Fig. 3). As

illustrated in Fig. 4, the silver ingot exhibits wrinkles

of solidification on the plain upper surface and some

cavities with small remains of charcoal and wood on

the bottom cone surface. The wood could be attrib-

uted to the tree species, Prosopis juliflora (Sw.) DC,

designated by the inhabitants in South America as

`̀ Mesquite, Cuji'' (D. Grosser, Institut fuÈr Holz-

forschung, UniversitaÈt MuÈnchen, Germany, private

communication, 1998).

Metallographic examinations of bits of the above

described silver and gold ingots revealed typical

dendritic cast structures (Fig. 5). As predicted by

the constitution of the silver±copper phase diagram

in Fig. 6 [63], the microstructure of the silver ingot

is heterogeneous, containing dark primary crystals

rich in copper (WDS analyses yield a solid solution

of 8% Ag in 92% Cu) that are embedded in an

eutectic mixture of bright silver and dark lamellar

copper crystals (Fig. 5a). The dendritic microstruc-

Fig. 2. Phase diagram of the ternary gold±silver± copper

system showing the semicircular-shaped a1 + a2 eutectic

miscibility gap AK2B at 800°C and isotherms of the

miscibility gap at lower temperatures [61]. EK1 denotes

the monovariant eutectic curve describing the three-phase

equilibrium a1 + a2 + L formed below 800°C. K1 is the

eutectic melt that is in equilibrium with the critical solid

solution a. a, a1, a2, and L denote, respectively, solid

solutions and the melt. The points of composition 1± 7 refer

to the `̀ gold'' ingot and some `̀ gold'' artifacts.

Fig. 3. Side views (schematically): (top)`̀ silver'' ingot and

(bottom) `̀ gold'' ingot.

Fig. 4. Cleaned `̀ silver'' ingot. (a) View on the plain upper

surface showing wrinkles of solidification. (b) View on the

convex bottom cone surface revealing remains of charcoal

and wood.


ture of the gold ingot shows solid solution segrega-

tion (Fig. 5b). WDS analyses indicate that the

compositions of the dark primary crystals (47.7%

Au, 6.0% Ag, and 45.7% Cu) and the solidified

bright residual melt (46.1% Au, 19.9% Ag, and

33.1% Cu) differ markedly in the copper and silver

concentrations, whereas the gold concentrations are

only slightly different. These data can be understood

by consulting the constitution of the ternary gold±

silver±copper system [62,74]. From temperature vs.

copper concentration sections showing the liquidus

and solidus for several gold concentrations [62], it

can be suggested that from a melt exhibiting the

composition of the investigated gold ingot (48.4%

Au, 12.7% Ag, and 39.0% Cu), primary crystals,

which are richer in copper than the solidified resi-

dual melt, should be formed.

Noticeable is the observation that in the structures

of both ingots, many cavities and copper oxide

particles are present. Inspecting the concentration

data in Table 2, it is evident that the bulk chemical

compositions of the gold and silver ingots are not

representative for any of the materials used in the

manufacture of the investigated objects. For the gold

artifacts, this is illustrated in the ternary Au±Ag±Cu

phase diagram in Fig. 2 by the array of points of

composition for the gold ingot (point 1) and some

objects (points 2±7). The scatter of compositional

data reflects the skill of the Moche metalsmiths to

smelt and work alloys of copper with gold and silver

in a wide range of concentrations.

Moche metalsmiths used copper extensively, not

only as a base metal in alloys with gold (tumbaga) or

with silver, but also for the manufacture of copper

objects, such as tools, implements, and weapons [29].

Correspondingly, such utilitarian items were also

found in the tomb of the `̀ Lord of SipaÂn.'' The

functional copper objects investigated in this work

(Table 1) were made from rather pure copper, sug-

gesting that the material had been smelted from an

oxidic ore or from copper carbonate ore. Only one

Fig. 5. Scanning electron micrographs of the cast structures of the `̀ silver'' and `̀ gold'' ingots shown in Figs. 3 and 4. (a) Two-

phase structure of the copper± silver alloy with primary dendritic crystals rich in copper (dark) embedded in an Ag ±Cu eutectic

mixture. (b) Dendritic structure of the gold± silver± copper alloy showing solid solution segregation. Sample (a) polished,

viewed with backscattered electrons; sample (b) etched in saturated potassium dichromate solution + HCl (5:1).

Fig. 6. Phase diagram of the eutectic silver± copper sys-

tem [63].

Fig. 7. Cleaned coffin straps. With the permission of the

RGZ, Mainz.


item contained small amounts of arsenic. Since this

object (copper rattle pellet) was manufactured before

AD 300, it is less probable that the copper±arsenic

alloy was smelted intentionally. According to Lecht-

mann [33] and Shimada and Merkel [71], the Moche

metalsmiths seem to have experienced and used

copper±arsenic alloys probably only at late Moche

times. The large-scale production of these alloys

began much later, around AD 900, when the SicaÂn

culture flourished on the north coast of Peru.

The dominating features in Moche metallurgy

and metalworking technique were the fabrication

and use of high-quality thin sheet metal and, in

particular, the surface color of the objects. This is

impressively demonstrated by the treasure of artifacts

from the tomb of the `̀ Lord of SipaÂn,'' appearing

(after restoring) in gold and silver splendor. In the

present study, it could be confirmed that the Moche

artisans were masters in the gilding and silvering of

objects. Examples for the application of two sophis-

ticated techniques [29,30] were detected: (i) the

electrochemical gilding of copper objects (electro-

chemical replacement plating) and (ii) the gilding or

silvering of objects made of copper±gold±silver

(tumbaga) or copper±silver alloys, respectively, by

selective removal of copper from the near-surface

regions of the items (depletion gilding or silvering).

It was found that in most cases, the development of a

gilded or silvered surface on the investigated artifacts

was an inevitable consequence of the processing

technique including alternating hammering, anneal-

ing, and pickling off the surface copper oxide formed

in their process.

4. Working of copper

4.1. Functional objects

Among the investigated copper objects of func-

tional nature (Table 1) are coffin straps (Fig. 7),

which were used to lash together the wooden planks

of the Lord's coffin [40,45]; spacer bars, which were

used to stabilize a beaded pectoral and to keep

multiple strands of shell beads (made from spondylus

mussel shells) parallel to one another [40,45]; and the

handle of a fan. In spite of partial heavy deteriora-

tion, comprising both surface layer and bulk corro-

sion products of copper, the examined objects, in

general, exhibited a residual metallic copper core.

This is illustrated in Fig. 8a and b for the handle of a

fan and a coffin strap, respectively. The metallic core

of the handle of the fan was found to have the

structure of a deformed material with numerous

cuprite precipitates (Fig. 8c) that are aligned parallel

to the longitudinal axis of the handle indicating the

direction of deformation. Many cuprite particles

arranged parallel to the object's axis were detected

also in the metallic structures of the coffin straps and

spacer bars showing that these items, too, were

fabricated from cast copper material by hammering.

However, these metallic cores were completely

recrystallized, as documented in Fig. 8d, for the

sample of a coffin strap. This gives evidence of a

final annealing treatment of the coffin straps and

spacer bars with the aim to make the materials

ductile. Correspondingly, low Vickers hardness num-

bers were measured in the areas of the metallic

remains of the examined coffin strap (66 HV 0.1 to

82 HV 0.1) and spacer bar (95 HV 0.1). Much higher

was the hardness of the metallic handle of the fan

(154 HV 0.1) that was, in the final state, deformed.

Considering the function of the described objects, it

seems reasonable that the handle of the fan was left

in a final work-hardened state, whereas the coffin

strap and spacer bar finally were soft-annealed to

allow bending.

Examples for objects fabricated from copper by

casting were the head of a spear and a rattle pellet. The

investigated fragment of the spearhead, shown in Fig.

9, was roughly cleaned. It was 18 mm long, exhibiting

a circular cross section with a diameter of 3.5 mm at

the lower end and of only 1.4 mm at a distance of 1

mm below the tip of the spear. The cross-sectional

view of the spear in Fig. 10a reveals an extended

cavity in the center and some notches at the outer

surface of the spear, which can be interpreted as

casting flaws. As shown in Fig. 11a, the notches are

covered with a layer of blue±green malachite/para-

tacamite, indicating that they were already present

when the spear had been ready-fabricated.

The metallographic examination of cross and

longitudinal sections of the spear fragment combined

with EDS analyses revealed that the item had exten-

sively transformed into corrosion products. Inspect-

ing Fig. 11a, it can be concluded from the brown±

red color that cuprite (Cu2O) is the dominating

species in the bulk of the spear. The structure

consists apparently of many fine grains. This is

confirmed by the scanning electron micrograph of

a fracture surface at higher magnification in Fig. 10b.

In contrast, the tip of the spear shows large areas of

compact blue±green malachite/paratacamite and red

cuprite (Fig. 11b).

Copper pellets were found inside a series of

objects from the royal tomb, e.g., in the cones

attached at the lower edge of the banner shown in

Fig. 14 (see Section 4.2), in human-head-shaped

beads (Fig. 21), peanut beads (Fig. 25), single bells,

and bells as parts of backflaps (M. Fecht, RoÈmisch-

Germanisches Zentralmuseum (RGZ), Mainz, Ger-

many, private communication, 1998). They were


intended to give the objects the function of rattles.

The investigated pellet (diameter: 12 mm) stemming

from an ornamental cone of the banner was covered

with a crust of cuprite and malachite/paratacamite. It

had been cast from a copper material containing, on

an average, about 1.5% arsenic. The cross section

Fig. 11. Light micrographs of spear fragments, viewed in polarized light. (a) Detail of the cross section in Fig. 10a showing red

cuprite in the materials bulk and green malachite/paratacamite corrosion products covering the spear and the notch surfaces. (b)

Longitudinal section of the near-tip area of the spear exhibiting heavy corrosion (red: cuprite, blue±green: malachite/

paratacamite). Samples (a) and (b) polished. (Magnification bars are 100 and 400 mm, respectively.)

Fig. 8. Light micrographs of longitudinal sections of the handle of a fan and of a coffin strap, viewed in polarized light. (a,b)

Corrosion products encase the metallic core of the samples. (c) The copper core of the handle of the fan is heavily deformed,

exhibiting numerous aligned cuprite particles. (d) The copper core of the coffin strap shows a recrystallized structure with

annealing twins and many aligned cuprite particles. Samples (a) and (b) polished, sample (c) etched in 20% ferric chloride

solution, and sample (d) color etched in Klemm III reagent. (Magnification bars measure 200, 1000, 50 and 40 mm, respectively.)


through the pellet in Fig. 12a shows a large cavity in

the bulk that obviously is a casting flaw. This cavity

is connected to the surface of the pellet by a fissure.

Inside and along these defects, much brown±red

cuprite had formed. Etching of the sample section

revealed the occurrence of a cored dendritic cast

structure with pronounced solution segregation in

the center of the pellet segment and with weak signs

of deformation and recrystallization (Fig. 12b). In the

near-surface area, a recrystallized structure with

extended parallel segregation bands could be made

visible by Klemm III color etching (Fig. 12c). In

WDS line scans, the segregation is reflected by

periodical changes in the arsenic content, the con-

centrations ranging between 0.2% and 1.8% (Fig.

13). These structural features give evidence that the

cast copper pellet was brought in its final shape by

working and was subsequently annealed.

It should be noted that among the investigated

objects excavated from the tomb of the Lord of SipaÂn,

the rattle pellet was the only one that was fabricated

from copper containing small amounts of arsenic. It

may be supposed that the arsenic had been added to

the copper accidentally and not intentionally. Follow-

ing the present knowledge [33], the Moche smiths

began to experience and use arsenical copper only in

the late Moche times.

Fig. 9. Cleaned head of a spear (length: 14 mm, diameter at

the lower end: 3.6 mm).

Fig. 10. Scanning electron micrographs of polished cross

sections at the lower end of the spear fragment showing (a)

an extended cavity in the center and notches at the surface

of the spear and (b) the fine grain structure at the surface

of a fracture.


4.2. Banner with ornamental platelets

A series of objects found in the tomb of the Lord of

SipaÂn was identified to be manufactured of gilded

copper sheet. Examples are some human male figures,

numerous platelets, and many rattle cones that were

sewn on a shirt-like garment of the Lord or were part

of two banners. One of the banners, after cleaning and

reconstructing, is shown in Fig. 14. It is 54 cm broad

and 48.5 cm high; originally, it consisted of two or

more layers of coarse cotton cloth on which a human

male figure and many platelets, all made of gilded

copper sheets, were sewn. The central figure in high-

Fig. 16. Cross section through the ornamental platelet in Fig.

15 revealing a microstructure with copper corrosion

products in the bulk and above the original surface of the

platelet that is marked by a thin `̀ gold'' film (2± 6 mm thick).

Sample polished and viewed in polarized light. (Magnifica-

tion bar is 100 mm.)

Fig. 14. Cleaned and reconstructed banner with numerous

ornamental platelets and a central human male figurine in

high-relief (width: 54 cm, height: 48.5 cm).

Fig. 12. Light micrographs of cross sections through a copper pellet, viewed in polarized light. (a) Metallic bulk containing a cavity

filled with red cuprite. (b) Cored dendritic cast structure in the center of the pellet segment exhibiting solid solution segregation of

arsenic in copper. (c) Recrystallized structure in a near-surface region showing zones of segregation worked out into bands. Sample

(a) polished; samples (b) and (c) color etched in Klemm III reagent. (Magnification bars are 1000, 100, and 200 mm, respectively.)


relief, which is assembled from individual pieces, is

richly decorated and exhibits a flat helmet, raised

arms, and the feet pointing out to the sides. The

ornamental platelets surrounding the small figure are

approximately quadratic; those located along the outer

edges of the banner were each embossed to show the

relief of an ulluchu fruit. Along the lower edge of the

banner was a row of attached gilded copper cones (not

visible in Fig. 14) serving as decorative fringe [40].

The cones exhibited a banded surface relief; they were

hollow and contained copper pellets that gave them

the function of rattles (see Functional objects).

When the banner was excavated, the metallic

items were covered with a dark green patina layer.

As an example, Fig. 15 shows an ornamental platelet

with an ulluchu fruit relief (dimensions: 32� 29

mm2). In a small area at the center of the fruit, where

the green corrosion crust has been removed, the

original surface of the gilded copper platelet is visible

(bright). The microstructure of a polished cross sec-

tion through the platelet, viewed in polarized light, is

presented in Fig. 16. It is seen that the item, which is

approximately 0.4 mm thick at the center, is heavily

corroded throughout. A thin `̀ gold'' film (2±6 mm)

clearly marks the original surface of the platelet and

separates the dark-brown-colored corrosion species in

the bulk of the platelet from the thick corrosion layers

that developed above the gold film. The exterior

corrosion crust consists mainly of reddish-brown

and orange cuprite (copper (I) ± oxide, Cu2O),

green-to-blue malachite (basic copper carbonate,

CuCO3�Cu(OH)2), and paratacamite (basic copper

chloride, CuCl2�3Cu(OH)2) [45]. The metallographic

examination of some other samples confirmed that

the copper platelets have, in general, completely

decomposed into corrosion products during the

nearly 1700-year-long burial. Only the thin gold films

withstood the corrosion attack, enabling a restoration

of the platelets to give them a lustrous appearance

similar to what they had once been.

It is of interest to note that the transformation of

copper into corrosion products results in an increase

of volume; e.g., the ratio of the molar volumes of

copper and cuprite amounts to 1:2. In spite of this,

the gold films obviously have maintained their

original shape (Fig. 16). Therefore, it must be

assumed that in a first stage of the corrosion of the

platelets, copper ions diffused through the gold film

to the outer surface where they were oxidized and

formed a cuprite layer. This layer increased in

thickness and then lost adherence to the surface. In

a later stage, in the presence of carbon dioxide,

water, and chlorides, cuprite partially transformed

into malachite/paratacamite. In addition, the corro-

sion of copper took place also in the bulk of the

platelets beneath the gold film. The growth of the

inner voluminous copper oxides was supported by

the many lattice defects, especially vacancies and

pores that had formed during the preceding outward

diffusion of copper [45].

There is no doubt that the Moche metalsmiths

crafted the copper platelets by applying the sheet

technique. This method comprises the shaping of the

original cast ingot into sheet metal by alternate

hammering and annealing. Actually, the cross-sec-

tional views through some corroded platelet frag-

ments revealed a layered structure that indicates the

previous heavy deformation of the material (Fig. 17).

Frequently, in such micrographs, a weak recrystal-

lized structure of large grains was seen to be super-

Fig. 13. Examination of the segregation bands shown in Fig.

12c by a WDS line scan of the arsenic concentration vs.

distance across a small area of the sample.

Fig. 15. Ornamental platelet (32� 29 mm2) with an ulluchu

fruit relief covered with a green patina layer and showing a

small area of the bare original gilded surface.


imposed on the prevailing layered deformation struc-

ture. This observation suggests that the material was

annealed subsequent to the copper working. Addi-

tional indications of an annealing treatment can be

seen in Fig. 18, which shows a fracture surface across

a small residual metallic region of a platelet fragment.

The forced fracture is of the mixed type and exhibits

large recrystallized grains and twins as well as many

pores. The pores are frequently elongated in one

direction, thus indicating the previous directional

working of the material.

Special attention was focused on the characteris-

tics of the gold films encasing the platelets. The

inspection of microstructures like those presented in

Figs. 16 and 19 shows that the thin gold films on the

whole are rather uniform and even, but they exhibit

short distance variations in thickness from 2 to 6 mm.

Due to defects, the films are not continuous. Strik-

ingly, the gold films closely follow the original sur-

face of the copper platelets and even cover their

edges. Thus, the films resemble modern deposits

produced electrochemically [64±66].

EDS and WDS analyses revealed that the coat-

ings consist not of pure gold but a gold±copper

solid solution (containing some silver) that changes

in composition across the film. For example, near

the interface between the film and the (corroded)

copper the composition was 70% Cu, 28% Au, and

2% Ag, whereas in the center of the film the

composition was 56% Cu, 41% Au, and 3% Ag.

From these results, it may be concluded that the

platelets were heated after being coated with the film

of gold. Due to this treatment, interdiffusion of

copper and gold across the gold±copper interface

took place, resulting in the formation of a transient

solid solution zone. This process was accompanied

by an increase of the thickness of the original

deposited gold film. The interdiffusion between the

copper and gold can be expected to have occurred

preferentially along grain boundaries. Thus, some of

Fig. 17. Light micrograph of the cross section of a platelet

fragment showing the layered structure of the corroded bulk

of the material. Sample polished and viewed in bright field.

Fig. 18. Scanning electron micrograph of a recrystallized

residual metallic region in the bulk of a platelet showing the

surface of a forced fracture (mixed type) with large grains,

twins, and elongated pores.

Fig. 19. Cross section of a platelet fragment revealing

details of the `̀ gold'' film> embedded in the corrosion

products of copper. The gold film closely follows the original

surface of the copper substrate and covers even the edges.

Sample etched in 50% aqueous HNO3 solution and viewed in

bright field.

Fig. 20. Scanning electron micrograph of the near-surface

region of a platelet fragment revealing a bamboo-like grain

structure of the `̀ gold'' film. Sample etched in 50% aqueous

HNO3 solution.


the tiny protrusions of the gold±copper film directed

into the interior of the platelet (Fig. 19) may reflect

former grain boundaries of the metallic copper

intersecting the surface of the platelet. Remarkably,

the decoration film shows a bamboo-like structure

(Fig. 20) that might be considered as a further

indication for an annealing treatment of the platelets

subsequent to the gilding procedure. It is possible

that the abovediscussed signs of recrystallization in

the bulk of the platelets (Fig. 18) are caused also by

the heating of the platelets after their coating with

the gold film.

Of great interest is the method applied by the

Moche metalsmiths to gild the copper objects. This

problem has been treated previously by Lechtman

[29,64±66] in her study on gilded copper objects of

Moche style found at Loma Negra, located in the

Piura Valley in northern Peru. The Loma Negra

copper objects were also made of hammered sheet

metal and exhibited remarkably thin (0.5±2.0 mm)

and uniform gold (or silver) coatings that, in their

characteristics, were similar to those of the gold films

on the SipaÂn ornamental platelets. Probably, these

objects were manufactured by the Moche at about the

same time when the artifacts stemming from the tomb

of the `̀ Lord of SipaÂn'' were made [40]. By perform-

ing experiments designed to reproduce the gilding of

copper, Lechtman demonstrated that the Moche

metalsmiths achieved the surface gilding by a sophis-

ticated electrochemical deposition method that today

is referred to as electrochemical replacement plating

[29,64±67].

Following the studies of Lechtman, the Moche

metalsmiths presumably dissolved gold (which con-

tained some silver) in aqueous mixtures of corrosive

minerals, such as common salt (NaCl), potassium

nitrate (KNO3), and potassium aluminum sulfate

(KAl(SO4)2�12H2O). These minerals were available

in the desert environment at the north coast of Peru.

It should be noted that in mixing the above minerals

in equal parts, a highly acidic aqueous solution is

obtained containing trivalent gold ions from which

chloroauric acid (H(AuCl4)�3H2O) would crystallize.

Therefore, Lechtman, in her experiments, alkalized

the solution to a pH value of 9. Only then did she

succeed in coating a copper sheet with a film of gold

approximately 1 mm thick, when the sheet was

dipped for 5 min in a gently boiling solution. To

bond the film permanently to the copper surface, the

object was heated at a temperature between about

500°C and 800°C at which solid-state diffusion of

copper and gold could proceed. Due to this treatment,

a transient gold±copper zone developed at the sur-

face and the copper objects began to recrystallize.

Both phenomena were observed on the investigated

ancient items.

The electrochemical replacement plating can be

characterized by the ion exchange reaction [68]:

2Au3� � 3Cu) 2Au0 � 3Cu2�

according to which copper is dissolved in the

electrolytic solution as ions, while gold ions from

the solution are deposited and neutralized on the

copper surface. The reaction is based on the large

potential difference between gold (noble) and copper

(less noble) in the electrochemical series of chemical

elements. It requires anodic (positive) and cathodic

(negative) areas, which are provided by different parts

of the same copper surface. As supposed by Lechtman

[29], small pits or irregularities on the surface of the

copper may act as anodes. The anodic activities

should continue as long as possible to favor deposition

of gold onto the adjacent cathodic surface areas.

5. Working of copper±silver alloys

5.1. Human-head beads

The investigated ``silver'' human-head beads

belong to a necklace of 10 beads. Fig. 21 shows one

of them after cleaning and restoring. When the head

beads were excavated, they were covered with green-

colored crusts containing copper corrosion products,

indicating a high copper content; some of the beads

had even disintegrated into fragments. Made from thin

sheets of a copper±silver alloy by embossing, punch-

ing, and chasing, the head beads were hollow and

composed of two halves (one for the face and one for

the back of the head) that were joined metallurgically

along their edges. Inside each of the beads, two copper

Fig. 21. `̀ Silver'' human-head-shaped bead after cleaning

and restoration (width: 5.1 cm, height: 4.0 cm) that belongs

to a necklace of 10 beads.


pellets were placed to stabilize the necklace and to

give it the function of a multirattle when moved. The

shapes, dimensions (ranging from 5.0 to 5.2 cm in

width and from 4 to 5 cm in height), and facial

features are similar but differ from head to head.

These slight variations suggested that the Moche

metalsmiths had crafted the beads by using mold-

shaped beds and by subsequently working out the

details individually. Originally, the head beads were

kept apart by spacer tubings that were made of thin

sheets of metal (thickness: 0.15 mm) of the same

copper±silver alloy as used for the head beads.

For studying the structure and chemical composi-

tion of both the human-head beads and the spacer

tubings, several fragments of these items were

sampled. The metallographic examination of many

cross sections revealed two different types of micro-

structures. The first type (Fig. 22) is characterized by

a lamellar microstructure typical for a drastically

deformed heterogeneous material. This structure is

reflected in WDS line scans (Fig. 23) by periodical

changes in the copper and silver concentrations. The

bright lamellae, which frequently are disintegrated

into stringers and globules (Fig. 22 a and b), are

found to be rich in silver, while the dark broader

layers are rich in copper. The copper is partially

transformed into its corrosion products, cuprite and

malachite/paratacamite. This can be concluded by

examining the microstructure of polished sample

sections with polarized light.

The occurrence of the lamellar microstructure can

be understood by considering that the human-head

beads and the spacer tubings were crafted from thin

sheet metal. The sheet material itself was made from

the cast ingot of a copper±silver alloy having the

probable composition of 79% Cu, 20% Ag, and 1%

Au. The concentrations of copper and silver were

estimated from the fractional areas of the copper-rich

and silver-rich phases appearing in cross-sectional

views of fragments of the objects (Fig. 22a). As

predicted by the constitution of the eutectic silver±

copper system (Fig. 6) [63] and illustrated by the

exemplary cast structure in Fig. 5a, the melt of this

alloy is expected to solidify through the formation of

primary dendritic copper-rich crystals and an eutectic

mixture of silver and copper crystals. When the ingot

was alternately hammered and annealed, the consti-

tuents became increasingly elongated in the direction

of the material flow. After many cycles of hammer-

ing and annealing, the original cast structure was

transformed into a structure exhibiting an increasing

phase separation into alternating silver-rich and cop-

per-rich lamellae. This microstructure was character-

ized by large interfacial areas between the two

phases with a high interfacial free energy. Hence,

the disintegration of the thin silver lamellae into

small stringers and globular particles, as observed

Fig. 22. Scanning electron micrographs of the polished cross section through a head-shaped bead fragment. (a) Lamellar structure

of the heavily deformed material consisting of silver-rich lamellae, stringers, and globules (light) embedded in copper-rich layers

(dark). (b) Detail of the section in (a) showing the morphology of the silver-rich phase (light).

Fig. 23. WDS line scans of the concentrations of copper

(Cu), silver (Ag), and gold (Au) as a function of the distance

across a small area of a layered structure like that shown in

Fig. 22.


in Fig. 22b, can be attributed to the tendency to

minimize this energy.

Another direct consequence of the metalworking

by alternate hammering and annealing was the for-

mation of a silvered surface on the sheet metal.

During the intermediate annealing treatments to keep

the material malleable, copper oxide formed on the

surface. The Moche metalsmiths probably removed

the oxide scales using acidic plant juices or stale

urine that had degraded to ammonia. After many

cycles of hammering, annealing, and pickling off the

copper oxide, the copper±silver sheet in the near-

surface region was depleted of copper and enriched

with silver. As a result, the object that was manu-

factured from this sheet metal appeared as if it were

made of pure silver (depletion silvering) [29],

although the copper ± silver alloy contained only

about 20% silver.

The second type of microstructures (Fig. 24)

detected in some other fragments of human-head

beads, but not of spacer tubings, exhibits the char-

acteristics of a cast material. Using EDS and WDS

analyses, the large light- or dark-grey grains could be

identified as being rich in copper, while the white

structural elements are silver-rich. The copper was

found to have at least partially transformed into

corrosion products. An estimation of the silver con-

centration again led to a value of about 18%. Thus,

both structures observed in fragments of human-head

beads obviously are based on the same original

copper±silver alloy and, moreover, the pseudo-cast

structure must have developed from the deformed

structure. By considering the features of the eutectic

silver±copper phase diagram in Fig. 6, it is evident

that this transition required an intermediate heating of

the material to a point at least above the eutectic

temperature of 779°C. As a result, the material

transformed from the solid into a semiliquid state in

which solid copper-rich crystals were embedded in a

silver-rich melt. After slow cooling, microstructures

like that shown in Fig. 24 can be expected to develop.

It may be assumed that the high-temperature treat-

ment of the material was performed locally to join the

two halves of a head-shaped bead along their edges.

Although this assumption could not be proven based

on an examination of the head-bead samples, such

joining was detected in the analysis of a `̀ silver''

peanut bead.

5.2. Peanut beads

The investigated `̀ silver'' peanut beads belong to a

necklace consisting of two strands, each with 10

beads. Five of them were made of `̀ gold '' and the

other five of `̀ silver,'' thus expressing the Moche's

pairing of gold and silver in a symbolic duality

[40,60]. In Fig. 25, a small section of the necklace is

reproduced after restoration. As found for the human-

head-shaped beads, the hollow peanut beads comprise

two halves that were joined metallurgically along their

edges. Moreover, these beads also contained copper

pellets and were made of thin sheets of a copper±

silver alloy. However, contrary to the case of the

Fig. 24. Scanning electron micrographs of the polished cross section of another head-shaped bead fragment. (a) Pseudo-cast

structure consisting of copper-rich crystals (light and dark grey) and a silver-rich eutectic mixture (light). (b) Detail of the section

in (a) showing partial corrosion of the copper-rich crystals.

Fig. 25. Cleaned and restored `̀ silver'' and `̀ gold'' peanut

beads (width: 6.8±8.7 cm, height: 3.1±4.1 cm) belonging to

a necklace.


investigated head beads, the silver concentration was

determined to be very high, amounting to about 80%.

The metallographic examination of peanut frag-

ments revealed structures that were typical for either

deformed or cast material. Fig. 26 shows a pseudo-cast

microstructure with large grains, which are partially

embedded in a mostly degenerated eutectic. Based on

EDS and WDS analyses, the grains were found to be

rich in silver. As with the head-shaped beads, the

occurrence of a pseudo-cast structure indicates that

in the manufacture of the peanut beads, an intermedi-

ate local heating of the material had been carried out

above the eutectic temperature of 779°C (see phase

diagram in Fig. 6). This heating was certainly neces-

sary to join the halves of the peanut beads.

Fig. 27 illustrates cross-sectional views through a

peanut fragment showing a joint that is composed of

the two parts of the peanut and a filler material

introduced between these parts. In Fig. 27a, the areas

of the peanut pieces are shown in bright field,

whereas the filler material is tinted red. It is seen that

the peanut pieces were joined in a configuration by

which the pieces were slightly spread out and slightly

overlapping along their edges.

EDS analyses carried out across the joint

revealed that the composition of the filler is only

slightly different from the composition of the peanut

material. These results suggest that both materials

originated from the same or similar alloys. The filler

does, however, exhibit a higher concentration of

defects than that of the two peanut pieces. In the

micrograph of Fig. 27b, viewed in polarized light,

the defects appear differently colored, indicating the

presence of cuprite, malachite/paratacamite, or cal-

cium carbonate. The small white areas simply repre-

sent bubbles. Most striking is the perfect union of

the two peanut parts mediated by the filler material.

This technique of joining certainly made great

demands on the skill of the Moche metalsmiths. In

particular, a reliable control of the local heating of

the joint was necessary to avoid complete melting of

the materials involved.

5.3. Ceremonial knife (tumi)

Another object examined, manufactured from a

copper±silver alloy, is the ceremonial knife (tumi)

shown in Fig. 28 after cleaning and restoring. The

tumi is photographed against a gold backflap and

together with some owl-head beads. In Moche art,

tumis are frequently depicted as being used to cut off

the heads of prisoners or human sacrifices. They were

also made from copper±gold±silver alloys. In the

tomb of the Lord of SipaÂn, the symbolic duality of

silver and gold objects is reflected by a pair of tumis

of comparable form and size (11.5 cm high for the

gold tumi and 12.0 cm for the silver tumi) [40,60].

Both tumis rested on the chest of the deceased Lord

together with four necklaces (see Fig. 42). The upper

narrow part of the silver knife in Fig. 28 serves as a

handle; the wider part at the bottom (8.2 cm broad) is

the blade. The cutting edge, however, is not sharp,

indicating that the tumi was not for use as a knife but

had the meaning of an ornamental object that could

have been worn at the belt. For this use, the top of the

handle is perforated, allowing to draw a loop of

cordage through the hole.

In Fig. 29, cross sections of a tiny sample

stemming from a region near the edge of the tumi

are represented. The microstructure in Fig. 29a,

viewed in bright field, shows the characteristic

structural features of the casting of a copper±silver

alloy consisting of primary dendritic crystals and an

eutectic mixture. EDS and WDS analyses revealed

that the light- and dark-brown primary crystals are

rich in copper (differing slightly in concentration),

whereas the light eutectic mixture, in which numer-

ous small dark copper-rich particles are embedded,

is rich in silver. Fig. 29b shows a detail of this

Fig. 26. Scanning electron micrograph of the polished cross section of a peanut fragment. (a) Pseudo-cast microstructure with

silver-rich crystals embedded in a eutectic mixture of silver and copper crystals. (b) Detail of the section in (a) showing the fine

lamellar structure of the eutectic mixture.


structure that can be compared with that of the cast

silver ingot in Fig. 5a. The concentration changes in

copper and silver and the constant concentration of

gold impurities are clearly reflected by the WDS line

scans in Fig. 30. Striking is the occurrence of a

broad near-surface zone that is practically free of

copper particles and contains about 90% silver. This

zone, which might be 15±40 mm deep (Fig. 29a),

gives the tumi the appearance of pure silver,

although the average silver content of the original

copper±silver alloy may be estimated to be lower

than 50%. To achieve the surface silvering, the

Moche metalsmiths probably removed the near-sur-

face copper by selective chemical dissolution. Con-

sidering the broad copper-depleted zone, it must be

assumed that the object was heated intermediately in

order to initiate the diffusion of copper to the surface

with subsequent oxidation of copper and etching

away the copper oxides that form in the process.

The metallographic results on the ceremonial

knife give evidence that this object was manufac-

tured by casting. This technique was considerably

less frequently applied by the Moche metalsmiths

than the sheet technique [29]. It is thought that

casting was done using an open mold. The edges

of the tumi were rounded by a subsequent hammer-

ing. As a consequence, the thickness of the ceremo-

Fig. 27. Cross section through the joined region of two parts of a peanut bead showing that the filler material contains a high

density of defects (bubbles and inclusions). Polished section viewed in (a) bright field; the filler material tinted red and in (b)

polarized light. (Magnification bar is 500 mm.)

Fig. 28. Cleaned and restored ceremonial `̀ silver'' ceremo-

nial knife (tumi) with a width up to 8.2 cm and a height of

12.0 cm. The tumi is photographed together with a `̀ gold''

backflap and some original owl's head beads.

Fig. 29. Cross sections through a tiny sample of the tumi

edge exhibiting a dendritic cast microstructure that consists

of primary copper-rich crystals (brown or dark-toned)

embedded in a eutectic mixture of copper and silver crystals.

(a) Sample color etched in Klemm III solution and viewed in

bright field (magnification bar is 30 mm). (b) Scanning

electron micrograph of polished sample.


nial knife decreases from the central areas (2.2±2.6

mm) to the edges (1 ± 2 mm). The mechanical

deformation is also reflected by the microstructure

in Fig. 29a, which shows that the copper-rich crys-

tals near the edge of the tumi are elongated parallel

to the surface.

6. Working of copper±gold±silver alloys

6.1. Headdress

Beneath the banner shown in Fig. 14, another

spectacular ornamental object was found in the tomb

of the Lord of SipaÂn (Fig. 31). It was covered with

green copper corrosion products, indicating a rather

high copper content. In spite of this, after cleaning

and restoring, the object exhibited a golden appear-

ance. The artifact consists of a large sheet of a

copper±gold±silver alloy shaped in the form of a

headless figure with extremely long and broad, raised

arms, with short legs, and feet that point sideways. It

is 36±65 cm broad and 42 cm high; the thickness is

about 0.3±0.4 mm. At the center of the object, a

small richly decorated male figure is worked out in

high relief. This figure is similar to that depicted on

the banner in Fig. 14. It may be noted that the gesture

expressed in the form of the basic metal sheet is

repeated in the central figurine. The function of this

object was uncertain [40], until quite recently the

artifact could be identified as part of a headdress

ensemble (M. Fecht, RoÈmisch-Germanisches Zentral-

museum, Mainz, private communication).

The metallographic investigation of fragments of

the headdress resulted in micrographs such as that

shown in Fig. 32. The cross sections, polished or

etched and viewed in polarized light or bright field,

respectively, reveal a layered structure that is drasti-

cally disturbed by widespread and voluminous green

corrosion products of copper (malachite/parataca-

mite). The apparently metallic parts of the material,

which exhibit in Fig. 32a the geometric array of

alternate light- and dark-brown layers parallel to the

surface, occur only in relatively small areas. In other

larger areas, the layers are disintegrated into smaller

pieces, as illustrated in Fig. 32b at a higher magni-

fication. Numerous cracks are present also in the

better-preserved parts of the material (Fig. 33), indi-

cating that the headdress ornament was heavily

damaged by stress corrosion cracking.

WDS analyses were performed across small sam-

ple areas that exhibited a rather intact layered struc-

ture. From the line scans in Fig. 34, it is seen that

marked periodical changes in the concentrations of

copper (48±66%) and gold (38±22%) occur, while

the low concentration of silver amounts to about 6%.

In general, the sum of all metal concentrations is only

weakly oscillating and yields 87±97%. The concen-

tration changes for copper and gold are similar in

magnitude, but opposite in sign. This coupling sug-

gests that the light- and dark-brown toned layers in

Fig. 32a originate from segregation zones in the

initial cast ingot, which were deformed by hammer-

ing during the manufacture of the headdress.

The assumption of an essentially segregation-

determined microstructure is supported by the fol-

lowing other arguments. The average composition of

the alloy from which the artifact was made was

estimated from WDS and ICP-OES analyses to be

60% Cu, 34% Au, and 6% Ag. Ignoring silver due

to its low concentration, the microstructure of the

original cast ingot can be expected to be governed

by the constitutional features of the gold±copper

system. This system is characterized by liquid and



from the edge across a small area of the sample in Fig. 29a

reflecting the broad silver-enriched zone at the surface.

Fig. 31. Cleaned and restored headdress (width: 36±65 cm,

height: 42 cm) consisting of a large sheet of a copper±

gold± silver alloy in form of a headless figure with a central

small figurine in high relief.


solidus curves showing a minimum at 20% Cu and

by complete miscibility of gold and copper in the

solid state above 410°C [63]. Thus, the melt of the

alloy under consideration should solidify through

the formation of a series of solid solutions, exhibit-

ing segregation. Considering the high average cop-

per concentration of about 60% lying above the

concentration of 20%, it is realistic to suppose that

the cast microstructure was composed of primary

dendritic copper-rich crystals embedded in the soli-

dified residual melt containing less copper and more

gold. During the subsequent processing of this

material to shape it into sheet metal by alternate

hammering and annealing, the structural elements of

the cast ingot having different chemical composi-

tions were elongated to form layers parallel to the

sheet surface as shown in Fig. 32a.

As a consequence of the metalworking by

repeated hammering and annealing, the surface of

the sheet metal took on a golden appearance [29]. As

with the silver human-head beads, copper oxide

formed on the surface during the intermediate anneal-

ing treatments that kept the material malleable.

Again, these oxide layers had to be removed by

pickling off in acid plant juices or stale urine that

had degraded into ammonia. After many cycles of

hammering, annealing, and pickling, the surface of

the copper±gold±silver sheet was depleted in copper

and, thus, enriched in gold and silver. Such a surface

layer, which is only about 2±3 mm thick, is visible in

the etched cross section of the headdress fragment in

Fig. 32b on the right side. The AES depth profiles in

Fig. 35 demonstrate that the gold concentration at the

surface increased to about 60 at.% (75 wt.%),

Fig. 32. Light micrographs of the cross sections through a fragment of the headdress. (a) Layered structure that is heavily

disturbed by voluminous inclusions of green copper corrosion products (malachite/paratacamite). (b) Structure decomposed in

many small particles. On the right hand side, an approximately 3-mm-thick layer (light) enriched in gold and silver is visible.

Sample (a) polished and viewed in polarized light; sample (b) etched in saturated potassium dichromate solution + HCl (5:1) and

viewed in bright field. (Magnification bars are 50 and 20 mm, respectively.)

Fig. 39. Light micrographs of the etched cross sections of a chin ornament fragment viewed in bright field. (a) Striated structure

due to solid solution segregation and material deformation exhibiting numerous aligned particles and lamellae (dark) of the silver-

rich phase and cuprite. Sample etched in 20% ferric chloride solution. (b) Similar section, etched in saturated potassium

dichromate solution + HCl (5:1), showing again a banded structure that, in addition, exhibits clear signs of recrystallization. At

both surfaces, white layers (20± 40 mm thick) are visible, which are enriched in gold and silver (see AES depth profiles in Fig. 40).

(Magnification bars are 100 mm.)


whereas the copper concentration decreased to nearly

10 at.% (4 wt.%). Also, the silver concentration

increased markedly at the surface to about 30 at.%

(21 wt.%). Therefore, the surface of the headdress

ornament appears in the luster of an Au 750 alloy (18

carat), although the average gold content in the bulk

of the object is actually poor (34 wt.% Au, 8.2 carat).

6.2. Chin ornament

The chin ornament under consideration was part of

the Lord's death mask. All items were found on the face

of the deceased in good condition, exhibiting a golden

appearance. The chin ornament was made of a large

sheet of a copper±gold±silver alloy hammered into

the shape of cheeks, mouth, chin, and upper neck of the

Lord (Fig. 36). It is maximal 19.5 cm broad and 16 cm

high; the thickness varies between 0.6 mm at the edge

and 0.9 mm near the center. The front side is not

polished and the back side of the object shows a nap-

like pattern, which obviously reflects the marks of the

bed used in the process of embossing. Moreover, some

long cracks at the edge of the lower part of the chin

ornament intensify the impression that this object was

in hurry±scurry, rather crudely worked, and meant

only for use in the funeral ceremony. In contrast, the

other parts of the Lord's death mask were finely crafted

from small sheets of metal by careful embossing and

chasing to image the eyes, the nose, and the band of

teeth. These items exhibit a polished front surface and,

with the exception of the band of teeth, the thickness

amounts to only 0.1 mm and less [40].

The scanning electron micrograph of the polished

section through a sample of the chin ornament, imaged

with backscattered electrons (Fig. 37a), reveals a

periodical alternating weak light- and dark-grey-toned

Fig. 33. Scanning electron micrograph of a detail in the

polished cross section shown in Fig. 32a illustrating the

disintegration of the material by stress corrosion cracking.


(Cu), gold (Au), and silver (Ag) as a function of the distance

across a small area of the sample in Fig. 32a that exhibits an

apparently intact metallic layer structure.

Fig. 35. AES depth profiles of the concentrations of copper


from the surface across a headdress fragment give evidence

of surface enrichment in gold and silver.

Fig. 36. Cleaned chin ornament with a width up to 19.5 cm

and a height of 16 cm belonging to the deceased Lord's

death mask.


contrast resulting in a striated structure. Embedded in

this basic pattern are light and dark inclusions that are

aligned parallel to the direction of the striae. These

inclusions have the form of lamellae, stringers, and

globules as can be seen for the white phase, at higher

magnification in Fig. 37b. The various elements of the

microstructures shown in Fig. 37a and b could be

identified by the evaluation of EDS and WDS analyses.

It was found that the dark phase is cuprite, Cu2O,

whereas the white phase is silver-rich.

The striated pattern in Fig. 37b is reflected by

WDS line scans of the copper (Cu), gold (Au), and

silver (Ag) concentrations (Fig. 38) showing periodic

variations of the copper and silver contents. The

traces of the line scans are marked in Fig. 37b by

the black beam. The changes in the concentrations of

copper and silver are similar in magnitude, but

opposite in sign. Apparently, they can be interpreted

as segregation zones that were present already in the

original cast ingot and that were deformed by ham-

mering and embossing the material during the man-

ufacture of the chin ornament (see the Headdress

section). The sharp peak of the silver concentration at

a distance of 31 mm, which is accompanied by a

marked decrease in copper and a slight decrease in

gold concentrations, is caused by a small silver-rich

inclusion. Since this inclusion is only about 1 mm

thick, the silver concentration is, by far, underesti-

mated by the WDS measurements. According to Fig.

37b, the silver-rich inclusions appear only in segrega-

tion zones that are rich in silver. They may have been

present, at least partially, already in the original cast

ingot. More probably, the silver-rich phase had pre-

cipitated during the process of shaping the material

by alternate cycles of hammering (embossing) and

annealing. By this working, the particles were elon-

gated and aligned. However, as seen in Fig. 37b,

many small particles exhibit a globular form. This is

essentially due to final heat treatments of the ready-

fabricated chin ornament (see next passage).

The silver±copper solid solution segregation is

clearly seen also in the light optical micrographs of

etched cross sections in Fig. 39. In addition, Fig.

39a shows the dark elongated and aligned cuprite

Fig. 37. Scanning electron micrographs of the polished cross section through a fragment of the chin ornament, imaged with

backscattered electrons. (a) Striated structure of the deformed material in which inclusions of a silver-rich phase (light) and

cuprite (dark) are aligned parallel to the direction of the striae. (b) Detail of the section in (a) showing that the silver-rich phase

(light) appears in the form of lamellae, stringers, and globules. The black beam marks the trace of the WDS line scans in Fig. 38.



across a small area of the striated structure in Fig. 37b.



from the surface of a chin ornament fragment.


and silver-rich inclusions, while in Fig. 39b the

weak pattern of a superimposed recrystallized struc-

ture is visible, suggesting that the chin ornament had

been finally annealed. Remarkable are the light

layers on the surface of the chin ornament in Fig.

39b, which could be identified by WDS, EDS, and

AES analyses as gold- and silver-rich films. The

AES depth profiles in Fig. 40 demonstrate that on

the surface the gold concentration is increased,

whereas the copper concentration is decreased. Also,

silver is remarkably enriched on the surface. Strik-

ingly, these concentrations are similar to those

measured at the surface of the headdress ornament.

Moreover, that object seems to have a similar

average chemical composition as the chin ornament.

However, by comparing the AES depth profiles in

Fig. 41. Cross-sectional view through a fragment of the chin

ornament that is heavily deteriorated on the left side. The

light micrograph shows that the gold- and silver-enriched

layer (light) covers both the exterior surfaces of the object

and the interior surfaces of a cavity. Sample etched in 20%

ferric chloride solution + H2O2 (10:1); viewed in bright field.

(Magnification bar is 200 mm.)

Fig. 44. Light micrograph of the sample section in Fig. 43b

shows, in bright field, a white± red pattern indicating solid

solution segregation. The pattern is weakly stretched in the

direction of material deformation. Sample etched in

saturated potassium dichromate solution + HCl (5:1). (Mag-

nification bar is 200 mm.)

Fig. 48. Light micrograph of a gold bead's cross section

showing a sweat-welded joint with filler material. Originally,

the filler had the shape of two rings. Sample polished and

viewed in polarized light. (Magnification bar is 100 mm.)

Fig. 50. Cross-sectional view of a gold bead fragment showing

a pseudo-cast structure. Sample etched in saturated potassium

dichromate solution + HCl (5:1); viewed in bright field.

(Magnification bar is 200 mm.)

Fig. 51. Cross-sectional view through a gold bead compris-

ing two sweat-welded joints. The modern bead was made by

attempting to reproduce the Moche processing methods. The

joints resemble those of the ancient beads. Section polished

and viewed in polarized light (11�).


Figs. 35 and 40, it is seen that for the chin ornament,

the concentrations in the near-surface region change

more moderately with the distance from the surface

than for the headdress ornament. Actually, from

micrographs, as shown in Figs. 32b and 39b, the

thickness of the gold- and silver-enriched scale is

determined as 20±40 mm for the chin ornament and

2±4 mm for the headdress ornament. For explaining

the relatively thick gold- and silver-enriched layers

on the surfaces of the chin ornament, it is assumed

that the Moche metalsmiths exposed the ready-

manufactured chin ornament to a final treatment

similar to that applied in the case of the ceremonial

knife. By alternately heating the object and chemi-

cally dissolving the formed copper oxides from the

object's surface, the Moche smiths probably

increased the thickness of the original thin decora-

tive surface layer. This suggestion is supported by

the cross-sectional view of a fragment of the chin

ornament that is in part heavily deteriorated. Fig. 41

shows that the gold- and silver-enriched layer (light)

covers both the exterior surfaces of the object and

the interior surfaces of the extended cavity on the

left side. In addition, the recrystallized grain struc-

ture, visible in Fig. 39b, supports the assumption of

final heat treatments of the object.

6.3. Ornamental disc

The ornamental disc studied is part of a necklace

consisting of 16 gold discs. The necklace is photo-

graphed in Fig. 42 together with two ceremonial

knives. It was found lying on the chest of the

deceased Lord. The gold discs were excavated in

well-preserved condition due to a high gold content

of about 61% (Table 2). The discs show a rather

perfect circular form. They are shaped slightly con-

vex on the front side, which is polished, whereas the

surface on the back side is dull. The outer edge of the

discs is rounded; the thickness increased from 0.9

mm at the circumference to about 1.3 mm at the

center. These values as well as the diameters (46±48

mm) and weights (21.5±28.5 g) exhibit only small

changes from one item to the other, indicating that

the discs had been manufactured by using mold-

shaped beds. It should be noted that each disc is

perforated with two tiny holes near one part of the

edge, which allowed the discs to be strung with two

parallel cotton strings. The holes are not perfectly

round but oval, suggesting that the necklace had been

used for a longer time.

Metallographic investigations were carried out on

a near-edge fragment of one of the discs. The scanning

electron micrograph of a polished cross section in Fig.

43a reveals many cuprite particles aligned in parallel

rows. This gives strong evidence of mechanical

deformation of the material. It is noteworthy that an

image taken by backscattered electrons shows only a

weak additional contrast. However, after etching the

sample, a white±black pattern appears. In light photo-

micrographs illuminated in bright field, a white±red

pattern is visible (Fig. 44) that is ascribed to solid

solution segregation. In this pattern, a weakly pro-

nounced preferred direction is observed that obviously

corresponds to the direction of deformation of the

material. As demonstrated in the scanning electron

micrograph in Fig. 43b showing a recrystallized grain

structure, the gold disc was finally annealed.

As a consequence of the manufacture of the gold

disc by hammering, intermediate annealing, and pick-

ling off the formed copper oxides, the surface became

depleted in copper and enriched in gold and silver

(for process of depletion gilding, see the Headdress

section). This is demonstrated by the AES depth

profiles in Fig. 45 showing that the gold concentra-

tion increases in a very small zone of about 2 mm to

about 82 at.% (90 wt.%), whereas the copper con-

centration decreases to 3 at.% (1 wt.%). Considering

silver, only a weak increase in concentration is

observed, reaching about 15 at.% (9 wt.%).

Fig. 42. Cleaned necklace with 16 `̀ gold'' ornamental discs,

photographed together with two ceremonial knives. The

discs exhibit diameters of 4.6± 4.8 cm.


6.4. Ornamental beads

Tiny gold beads were used by the Moche elite for

various applications, e.g., as links in bracelets. In Fig.

46, some beads are shown that exhibit a golden

appearance after the surface patina was coarsely

removed. The beads are hollow and have holes by

which they could be strung on strings. Each is com-

posed of two half shells that are joined along their

edges as indicated by the fissure along the circumfer-

ence of one of the beads in the center of the photograph.

Considering the different shape, size (average dia-

meter: 2.3±3.4 mm), quality, and composition of the

beads, it seems that the beads belong to various

production series. The beads shown in Fig. 46 were



from the surface of a disc fragment indicating surface

enrichment of gold and silver.

Fig. 46. Coarsely cleaned `̀ gold'' ornamental beads

(diameter: 2.3± 3.4 mm).

Fig. 43. Scanning electron micrographs of longitudinal sections of an ornamental disc fragment. (a) Numerous cuprite particles,

partially elongated and aligned parallel to the surface indicating the direction of previous deformation, sample polished. (b)

Etching of the sample in saturated potassium dichromate solution + HCl (5:1) reveals a recrystallized structure.


made of hammered sheet metal by shaping circular

pieces of the sheet into half shells and joining the shells.

Microstructural evidence for the use of hammered

sheet was found in some cross sections of beads. Small

copper oxide particles, pores, fissures, and cracks were

aligned parallel to the surface of the beads, indicating

the direction of the material flow during deformation.

Furthermore, in some of the samples examined, a weak

surface enrichment of gold and silver was revealed by

WDS line scans (Fig. 47).

Particular attention was paid to the question of

how the Moche smiths accomplished the joining of

the half shells of a bead. The metallographic exam-

ination of numerous cross sections of bead fragments

revealed that the Moche craftsmen joined the bead

halves by a technique that is a modification of modern

welding with a filler material [29,69,70]. Originally,

the filler consisted of two rings that were placed on the

edges of the two bead-halves. The two filler rings

were protruding beyond the interior and the exterior

surfaces of the beads, i.e., the inner diameter of the

rings was smaller than that of the bead and the outer

diameter of the rings was larger than that of the bead.

After the welding, the joints were structured, as

illustrated in Fig. 48, by a cross-sectional view. The

tiny ribbons that emanate as a pair from the joint and

extend into the interior of the bead were part of the

inner edges of the rings that obviously had bent over

and subsequently had curled during welding. It should

be noted that the third visible ribbon is a leftover

fragment of the rings. Originally, a pair of ribbons was

present also at the exterior surface of the bead.

However, these ribbons were removed by the Moche

smiths to make the surface smooth. According to Fig.

48, the ring-shaped filler material was made of an

extremely thin sheet metal having a thickness of

0.01±0.03 mm, whereas the thickness of the wall of

the bead halves near the joint was 0.07±0.10 mm.

EDS analyses showed that the average composition of

the filler material (75.2% Au, 12.0% Ag, and 12.8%

Cu) was only slightly different from the composition

of the bead material (71.3% Au, 12.7% Ag, and

16.0% Cu). Thus, both materials obviously originated

from the same or similar alloys.

An interesting aspect in the joining of the two

halves of a bead refers to the function of the ring-

shaped filler material. As indicated in Fig. 48, and

more clearly in the scanning electron micrograph in

Fig. 49, the filler obviously did not melt completely

during welding and, thus, could not produce a con-

tinuos fusion weld between both parts of the bead.

The circular-shaped defects in the wall structure are

bubbles, which probably have formed during weld-

ing. The welding technique utilized required reliable

temperature control to ensure that only the surfaces of

the rings and of the edges of the bead halves just

began to melt. The surface melting certainly started

on the rings because they were much thinner than the

wall of the bead, and because they were protruding

beyond the interior and exterior surfaces of the bead.

As shown in Fig. 49, the material of the bead

halves on both sides of the weld exhibits a weak

recrystallized grain structure indicating that no melt-

ing had occurred. This, however, is not typical for all

investigated ornamental beads. In some cases, the

`̀ temperature control'' obviously was not effective

enough to avoid partial melting. In Fig. 50, the etched

cross section of a bead fragment, viewed in bright

field, shows the structure of a material that apparently

had begun to melt. This pseudo-cast structure can be

compared with corresponding structures, which were

observed in the `̀ silver'' human-head beads and

peanut beads (Figs. 24 and 26).

The same type of welded joints, as detected in the

ornamental beads, was observed also by Lechtman et

al. [70] in their study of the tails of the `̀ Peruvian Gold

Jaguars'' and designated as sweat-welded joints. With

the help of a professional goldsmith, these authors

Fig. 47. WDS line scans of copper (Cu), gold (Au), and

silver (Ag) across a small near-surface area indicating a

weak gold and silver enrichment.

Fig. 49. Scanning electron micrograph of a detail in the cross

section in Fig. 48 revealing that the sweat-welding did not

produce a thorough union between the two parts of the bead.

Sample etched in Klemm III solution.


could reproduce experimentally the ancient welding.

At our institute, the sweat-welding technique was also

successfully reproduced with the help of a skillful

goldsmith. The results of these efforts are demonstrated

in Fig. 51 by presenting the cross section through a

`̀ self-made'' bead containing joints of high quality.

Using an alloy that had a composition of 75% Au, 15%

Ag, and 10% Cu, the partial steps in the manufacture of

the bead were chosen similar to those that were thought

to be part of the technical procedure applied by the

Moche smiths and that have been described above.

Comparing Figs. 48 and 51, it is seen that the joints of

the self-made bead are quite close in their visual

characteristics to the joint of the ancient bead.

Acknowledgments

The authors are grateful to Dr. K. Weidemann,

managing director of the RoÈmisch-Germanisches

Zentralmuseum RGZ, Mainz, for initiating this study

and to Dr. D. Ankner (RGZ) for his valuable support.

Our particular thanks go to M. Fecht (RGZ) for

helpful discussions. We greatly acknowledge the

technical assistance provided by A. Meyer, S.

KuÈhnemann, Dr. E. Bischoff, S. Haug, and B. Siegle,

Max-Planck Institut fuÈr Metallforschung, Stuttgart.

References

[1] Prem HJ. Geschichte Alt-Amerikas. MuÈnchen, Ger-

many: R. Oldenbourg Verlag, 1989.

[2] Schulze-Thulin A. Linden-Museum Stuttgart. Stuttgart,

Germany: Amerika-Abteilung, 1989. pp. 123±33.

[3] Townsend RF, general editor. The ancient Americas.

Art from sacred landscapes. The Art Institute of Chi-

cago, IL. Munich, Germany: Prestel Verlag, 1992.

[4] Morris C, von Hagen A. The Inca empire and its Andean

origins. New York: American Museum of Natural His-

tory, Abbeville Press Publishers, 1993. pp. 67± 84.

[5] Morris C, von Hagen A. The Inca empire and its Andean

origins. New York: American Museum of Natural His-

tory, Abbeville Press Publishers, 1993. pp. 215±23.

[6] Mosely ME. The Incas and their ancestors. The archae-

ology of Peru. London: Thames and Hudson, 1992/

1994. pp. 161±216.

[7] Shimada I. Pampa Grande and the Mochica culture.

Austin, TX: University of Texas Press, 1994.

[8] Bruhns KO. South America. Cambridge: Cambridge

Univ. Press, 1994. pp. 191± 9.


Univ. Press, 1994. pp. 174± 84.


Univ. Press, 1994. pp. 223± 9.

[11] Stone-Miller R. Art of the Andes from ChavõÂn to Inca.

London: Thames and Hudson, 1995. pp. 83±118.

[12] Masuda S, Shimada I. OÈ kologie und Zivilisation im

Zentralen Andenraum. In: SicaÂn-Ein FuÈrstengrab in

Alt-Peru. Eine Ausstellung in Zusammenarbeit mit

dem peruanischen Kulturministerium. ZuÈrich, Switzer-

land: Museum Rietberg, 1997, pp. 14± 31.

[13] Masuda S, Shimada I. OÈ kologie und Zivilisation im

Zentralen Andenraum. In: SicaÂn-Ein FuÈrstengrab in

Alt-Peru. Eine Ausstellung in Zusammenarbeit mit

dem peruanischen Kulturministerium. ZuÈrich, Switzer-

land: Museum Rietberg, 1997, pp. 25± 7.

[14] Benson, EP. The world of Moche. In: Townsend RF,

general editor. The ancient Americas. Art from sacred

landscapes. The Art Institute of Chicago, IL. Munich,

Germany: Prestel Verlag, 1992, pp. 303± 15.

[15] Donnan CB. Masterworks of art reveal a remarkable

pre-Inca world. Natl Geogr 1990;177:16±33.

[16] Alva W, Donnan CB. Royal Tombs of SipaÂn. Los An-

geles, CA: Fowler Museum of Cultural History, Univer-

sity of California, 1993, pp. 19± 25, 127± 41, 219± 27.

[17] Donnan CB. Moche art of Peru. Pre-Columbian sym-

bolic communication. Los Angeles, CA: Fowler Mu-

seum of Cultural History, University of California, 1978.

[18] Donnan CB. Ceramics of ancient Peru. Los Angeles,

CA: Fowler Museum of Cultural History, University of

California, 1992. pp. 56± 69.

[19] de Bock EK. Moche, gods, warriors, priests. Leiden,

the Netherlands: SMP Informatief Spruyt, van Man-

tgem and De Does, 1988.

[20] Grossman JW. An ancient gold worker's toolkit. The

earliest metal technology in Peru. Archaeology

1975;25:270± 5.

[21] Lothrop SK. Gold ornaments of ChavõÂn style from

Chongoyape, Peru. Am Antiq 1941;6:250±62.

[22] Lothrop SK. Gold artifacts of ChavõÂn style. Am Antiq

1951;16:226± 40.

[23] Jones J. Introduction. In: Jones J, editor. The art of Pre-

Columbian gold. The Jan Mitchel Collection. London:

Weidenfeld and Nicolson, 1985, pp. 11, 12.

[24] Jones J. Pre-Columbian gold. In: El Dorado. The gold

of ancient Columbia. New York: Center of Inter-Amer-

ican Relations and the American Federation of Arts,

1974. pp. 21± 31.

[25] Llorens SR. Untersuchungen an vorspanischen Gold-

objekten. In: El Dorado. Das Gold der FuÈrstengraÈ-

ber. Berlin, Germany: Dietrich Reimer Verlag, 1994.

pp. 69±81.

[26] Tushingham AD, Franklin UM, Toogood C. Studies in

ancient Peruvian metalworking. In: History, technol-

ogy, and art. Monograph 3. Toronto, Canada: Royal

Ontario Museum (ROM), 1979. pp. 1 ±42.

[27] Lechtman H. The Central Andes: metallurgy without

iron. In: Wertime ThA, Muhly JD, editors. The coming

of the age of iron. London: New Haven and London

Yale University Press, 1980. pp. 267±334.

[28] Lechtman H. Andean value systems and the develop-

ment of prehistoric metallurgy. Technol Cult 1984;25:

1 ±36.

[29] Lechtman H. Traditions and styles in Central Andean

metalworking. In: Maddin R, editor. The beginning of

the use of the metals and alloys. Cambridge, MA: MIT

Press, 1988. pp. 344± 78.


[30] Lechtman H. The materials science of material culture:

examples from the Andean past. In: Scott A, Meyers P,

editors. Archaeology of Pre-Columbian sites and arti-

facts. Los Angeles, CA: Getty Conservation Institute,

1994. pp. 3± 12.

[31] Jones J. Mochica works of art in metal: a review. In:

Benson EP, editor. Pre-Columbian metallurgy of South

America. Washington, DC: Dumbarton Oaks Research

Library and Collections, Trustees for Harvard Univer-

sity, 1979. pp. 53±104.

[32] Lechtman H. Issues in Andean metallurgy. In: Benson

EP, editor. Pre-Columbian metallurgy of South Amer-

ica. Washington, DC: Dumbarton Oaks Research Li-

brary and Collections, Trustees for Harvard University,

1979. pp. 1± 40.

[33] Lechtmann H. The production of copper± arsenic al-

loys in the Central Andes: highland ores and coastal

smelters? J Field Archaeol 1991;18:45±76.

[34] Muro PC, Shimada I. Behind the golden mask. SicaÂn

gold artifacts from BataÂn Grande, Peru. In: Jones J,

editor. The art of Precolumbian gold. The Jan Mitchel

Collection. London: Weidenfeld and Nicolson, 1985.

pp. 61± 7.

[35] Alva W. Discovering the New World's richest tomb.

Natl Geogr 1988;174:510± 48.

[36] Donnan CB. Unraveling the mystery of the warrior

priest. Natl Geogr 1988;174:550±5.

[37] Alva W, Fecht M, Schauer P, Tellenbach M. Das FuÈr-

stengrab von SipaÂn, Entdeckung und Restaurierung

(La Tumba Del SenÄor De SipaÂn, Descubrimiento Y

Restauracion). Mainz, Germany: Verlag des RoÈmisch-

Germanischen Zentralmuseums, 1989.

[38] Alva W. New tomb of royal splendor. Natl Geogr

1990;177:2± 15.

[39] Donnan CB. Royal Tombs of SipaÂn. Moche ornaments

of Peru. Ornament 1993;17:44±9, 115

[40] Alva W, Donnan CB. Royal Tombs of SipaÂn. Univer-

sity of Los Angeles, CA: Fowler Museum of Cultural

History, 1993.

[41] von Hase F-W. La tombe princiere de SipaÂn. ArcheÂol

Nouv 1994;2:58± 63.

[42] Alva W. SipaÂn. In: de Lavalle JA, editor. ColleccioÂn

Cultura `y Artes Del Peru. Lima, Peru: CervecerõÂa

Backus y Johnston, 1994.

[43] Alva W. SipaÂn, Descubrimiento e InvestigacioÂn. Lima,

Peru: Union de CervecceriaÂs Peruanas Backus y John-

ston, 1999.

[44] Longhena M, Alva W. Die Inka und weitere bedeu-

tende Kulturen des Andenraumes. Erlangen, Germany:

Karl MuÈller Verlag, 1999, pp. 16± 41, 264± 87.

[45] Kallfass M, HoÈrz G. Metallographic investigations of

ornamental and ceremonial objects from the Royal

Tombs of SipaÂn/Peru: Part 1. Introduction, sample pre-

paration and methods of investigation Ð studies on

copper objects (coffin straps, spacer bars of a beaded

pectoral). Prakt Metallogr (Pract Metallogr), 1994;31:

603± 49.

[46] Petzow G. Metallographisches, Keramographisches,

Plastographisches AÈ tzen. Berlin, Germany: GebruÈder

Borntraeger Verlag, 1994. pp. 42±55.

[47] Weck E, Leistner E. In: Metallographische Anleitung

zum FarbaÈtzen nach dem Tauchverfahren: Part 1.

FarbaÈ tzen nach Klemm. DuÈ sseldorf, Germany:

Deutscher Verlag fuÈr Schweiûtechnik, 1982;vol. 77.

pp. 46± 60.

[48] KaÈmpfe B, Hunger H-J. RoÈntgenfeinstruktur analyse.

In: Hunger H-J, et al, editors. AusgewaÈhlte Untersu-

chungsverfahren in der Metallkunde. Leipzig, Ger-

many: VEB Deutscher Verlag fuÈr Grundstoffindustrie,

1983. pp. 80± 121.

[49] Glocker R. MaterialpruÈfung mit RoÈntgenstrahlen unter

BeruÈcksichtigung der RoÈntgenmetallkunde. Berlin,

Germany: Springer-Verlag, 1971. pp. 188± 311.

[50] Reimer L. Scanning electron microscopy. Opt Sci

Springer-Verlag, Berlin, Germany 1985;4:365.

[51] Hunger H-J. Elektronenstrahl-mikroanalyse und raster-

elektronen-mikroskopie. In: Hunger H-J, et al, editors.

AusgewaÈhlte Untersuchungsverfahren in der Metallk-

unde. Leipzig, Germany: VEB Deutscher Verlag fuÈr

Grundstoffindustrie, 1983. pp. 175± 96.

[52] ``Kupfer.'' Gmelins Handbuch der Anorganischen

Chemie. System No. 60. Weinheim/Bergstrasse, Ger-

many: Verlag Chemie. Part A, Delivery 1, 1955, pp.

39, 166; Part B, Delivery 1, 1958, pp. 23, 203, 432.

[53] Riederer J. Analytische methoden in der kultur-

geschichtlichen forschung. In: Fresenius W, GuÈnzler H,

Huber W, LuÈderwald I, ToÈlg G, Wisser W, editors.

Analytiker-Taschenbuch, . Berlin, Germany: Springer-

Verlag, 1985;vol. 5. pp. 3± 32.

[54] Hoffmann H-J, RoÈhl R. Plasma-emissions-spektrome-

trie. In: Fresenius W, GuÈnzler H, Huber W, LuÈder-

wald I, ToÈ lg G, Wisser H, editors. Analytiker-

Taschenbuch. Berlin, Germany: Springer-Verlag,

1985;vol. 5. pp. 69±92.

[55] KloÈber J. Auger-elektronenspektroskopie. In: Hun-

ger H-J, et al, editors. AusgewaÈhlte Untersuchungs-

verfahren in der Metallkunde. Leipzig, Germany:

VEB Deutscher Verlag fuÈr Grundstoffindustrie, 1983.

pp. 229± 46.

[56] Seah MP, editor. Quantification of AES and XPS. In:

Briggs D, Seah MP, editors. Practical surface analysis,

Vol. 1: Auger and x-ray photoelectron spectroscopy.

Chichester, UK: Wiley; Frankfurt, Germany: Salle;

Aarau, Switzerland: SauerlaÈnder, 1990. pp. 201± 55.

[57] Hofmann S. Depth profiling in AES and XPS. In:

Briggs D, Seah MP, editors. Practical surface analysis:

Vol. 1. Auger and X-ray photoelectron spectroscopy.

Chichester, UK: Wiley; Aarau, Switzerland: SauerlaÈn-

der, 1990. pp. 143± 99.

[58] Veprek S. Restaurierung archaÈologischer Fundobjekte

im Niederdruckplasma. Phys Unserer Zeit 1993;24:

134± 9.

[59] Fecht M. ConservacioÂn y restauracioÂn. In: de Lavalle

JA, editor. ColleccioÂn Cultura y Artes Del Peru. Lima,

Peru: CervecerõÂa Backus y Johnston, 1994. pp. 234± 8.

[60] HoÈrz G, Kallfass M. Pre-Columbian metalworking in

Peru Ð ornamental and ceremonial objects from the

Royal Tombs of SipaÂn. JOM 1998;50:8±16.

[61] ``Gold.'' Gmelins Handbuch der Anorganischen

Chemie. System No. 62, Delivery 3. Weinheim/

Bergstrasse, Germany: Verlag Chemie, 1954, pp.

954± 60.


[62] Wise EM, editor. Gold. Recovery, properties, and ap-

plications. Princeton: Van Nostrand-Reinhold, 1964.

pp. 132± 7.

[63] Alloy Phase Diagrams. ASM Handbook, Vol. 3, Sec-

tion 2: Binary phase diagrams. Materials Park, OH:

ASM International, 1992. pp. 28, 68.

[64] Lechtman H. A pre-Columbian technique for electro-

chemical replacement gilding of gold and silver on

objects of copper. J Met 1979;31:154± 60.

[65] Lechtman H. New perspectives of Moche metallurgy

techniques of gilding copper at Loma Negra, Northern

Peru. Am Antiq 1982;47:3± 30.

[66] Lechtman H. Pre-Columbian surface metallurgy. Sci

Am 1984;250:38±45.

[67] Bray W. Techniques of gilding and surface enrichment

in pre-Hispanic American metallurgy. In: La Niece S,

Cradock P, editors. Metal plating and patination. Cul-

tural, technical and historical developments. Linacre

House, Jordan Hill, Oxford: Butterworth±Heinemann,

1993. pp. 182±92.

[68] Reid FH, Goldie W. Gold als OberflaÈche, Technisches

und Dekoratives Vergolden. Verfahren, Anwendung,

Bearbeiten der Schichten, Eigenschaften und PruÈfung.

pp. 85 ± 90 (revised and extended version of `̀ Gold

Plating Technology'').

[69] Welding, brazing, and soldering. ASM Handbook,

Vol. 6: Fundamentals of welding. Materials Park,

OH: ASM International, 1993. pp. 3 ±164.

[70] Lechtman H, Parson LA, Young WJ. Seven matched

hollow jaguars from Peru's Early Horizon. In: Linares

OF, editor. Ecology and the arts in ancient Panama. On

the development of social rank and symbolism in the

central provinces. Washington, DC: Dumbarton Oaks

Research Library and Collections, Trustees for Harvard

University, 1975. pp. 7 ±45.

[71] Shimada I, Merkel JF. Copper ± alloy metallurgy in

ancient Peru. Sci Am 1991;265:62± 8.

[72] Shimada I, Griffin JA. Precious metal objects of the

Middle SicaÂn. Sci Am 1994;270:60± 7.

[73] Donnan CB, Castillo LJ. Finding the tomb of a Moche

priestess. Archaeology 1992;45:38±42.

[74] Prince A. Critical assessment of copper± gold±silver

ternary system. Int Mater Rev 1988;33:314±38.


The Treasure of Gold and Silver Artifacts from Royal Tombs of Sipán, Peru. Hörz & Kallffass

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