Mineral Guide

8/3/2019 Mineral Guide

http://slidepdf.com/reader/full/mineral-guide 1/42

WJEC AS Mineral Guide

Mr.J.Roberts



Quartz (silicate)

1cm

Quartz (variety citrine)

Hardness 7, not

scratched by steel

No cleavage but shows

conchoidal fracture

Hexagonal crystals

terminated by pyramids

Rose quartz showing conchoidal fracture

5mm



Orthoclase Feldspar (silicate)

Hardness 6, barelyscratched by steel

2 cleavages intersecting at

90° results in blocky shape

Commonly flesh coloured

Crystals show

simple twinning2cm



Biotite Mica (silicate)

Hardness 2.5-3.0scratched by a

copper coin

Shows perfectbasal (parallel)

cleavage

Has a distinct

pearly lustre

Brown or black

in colour 2cm



Muscovite Mica (silicate)

Hardness 2.5-3.0scratched by a

copper coin

Shows perfect basal(parallel) cleavage

Has a distinct

pearly lustre

Whitish, straw or

silvery in colour 2cm



Hornblende (amphibole/silicate)

Hardness 5.0-6.0, justscratched by steel

2 sets of cleavages

intersecting at 60°/120°

Greenish black

in colour

1cm



Olivine (silicate)

Hardness 6.0-7.0,not scratched

by steel

Olive green

in colour

No cleavage

Olivine, Canary Islands

2cm



Andalusite/Chiastolite (silicate)

Hardness 6.5-7.5, notscratched by steel

Occurs as needle-likecrystals but square in

cross-section

Crystals have dark

inclusions in the centre,

like lead in a pencil

1cm



Garnet (silicate)

Hardness 6.5-7.5, not

scratched by steel

Rhombdodecahedral

crystal form, 12 faces

each one a rhombus

No cleavage

Red/brown or

green in colour

Almandine Garnet, Peru

2cm



Chlorite (silicate)

Hardness 2.0,

scratched by fingernail

Perfect basal

(parallel) cleavage

Greenish colour

Feels greasy when

rubbed between

the fingersAlteration product

from amphiboles,

pyroxenes and micasChlorite, Val Di Vizze, Italy

1cm



Calcite (carbonate)

Hardness 3, justscratched by a

copper coin

Perfect rhombohedral

cleavage, 3 planesintersect at 60°/120° to

give cleavage rhombs

Effervesces and gives off carbon dioxide when

dilute hydrochloric

acid is applied

1cm



Fluorite (halide)

Hardness 4, scratchedeasily by steel but not

by a copper coin

Perfect octahedral

cleavage, cubic crystalshave the corners

missing at a 45° angle

Fluoresces in ultra

violet light

Commonly purple, green

or yellow in colour 1cm



Halite or Rock Salt (halide)

Hardness 2.0-2.5,scratched by a

fingernail

Perfect cubic

cleavage, 3 planes

intersecting at 90°

Tastes salty when

put on the tongue

Halite, Neuhof, Germany

2cm



Gypsum (sulphate)

Hardness 1.5 -2.0, easily

scratched by a fingernail

Perfect basal

(parallel) cleavage

Often fibrous in

appearance (satin spar)

Arrow head/fish tailtwinned crystals common

2cm



Barytes/Barite (sulphate)

Hardness 3.0-3.5,barely scratched by a

copper coin

Dense for a non-

metallic mineral (4.5)

Often shows perfect

basal (parallel)

cleavage, occasionallydisplays 2 cleavages

Commonly shows

bladed crystal 2cm



Chalcopyrite (sulphide)

Hardness 4, not

scratched by a

copper coin

Black streak withgold strands within it

Metallic lustre

Greenish gold colour

Tarnishes to

peacock colours1cm



Iron Pyrite/Pyrite (sulphide)

Greenish black streak

Hardness 6.0, barely

scratched with steel

Metallic lustre

Brassy gold colour

Cubic crystals showstriated faces

Strikes fire (sparks)

with steel1cm



Galena (sulphide)

Perfect cubic

cleavage, 3 planes

intersect at 90°

Hardness 2.5, easilyscratched by a

copper coin

Lead grey streak

Very dense (7.5)

1cm



Haematite (oxide)

Hardness 5.5-6.5,

barely scratched by

steel

Cherry red streak

Metallic lustre

Often occurs as

kidney shaped masseswith a fibrous internal

structure 1cm



Identify this mineral 1

90°

Just scratched by steel

1cm




Greenish black streak, barely scratched by steel

1cm




Not scratched by steel, no cleavage

2cm




Scratched by steel but not by a copper coin

Cubic crystals with

edges truncated at 45°

2cm




2cm

Not scratched by steel, crystal has 12 faces



Identify this mineral 62cm

Barely scratched by steel, crystals often show simple twins

Cleavagetraces

90°




Feels dense, barely scratched by a copper coin

2cm




Just scratched by fingernail

1cm

1cm

Cleavage

directions




Not scratched by steel

2cm




2cm

90°

Cleavagetraces

Barely scratched by steel, crystals often show multiple twins




Cleavagetraces

2cm

Scratched by a copper coin




Barely scratched by steel, cherry red streak

2cm




Can be just scratched by a fingernail

1cm




Not scratched by steel, needle-like crystals

5mm




Scratched by a fingernail, fibrous/flaky, feels greasy

1cm



Name this mineral 17

Scratched easily by steel but not by a copper

coin, black streak with gold strands

2cm




1cm

Very dense, scratched by a copper coin, grey streak



Name this mineral 191cm

Reacts with acid, barely scratched

by a copper coin, 3 cleavages




1cm

Scratched easily by a fingernail, one plane of cleavage

Cleavage

traces



Name this mineral - Answers

1. Augite

2. Iron Pyrite

3. Olivine

4. Fluorite

5. Garnet

6. Orthoclase

7. Barytes

8. Halite

9. Hornblende

10.Quartz

11. Plagioclase

12. Biotite

13. Haematite

14. Muscovite

15. Chiastolite

16. Chlorite

17. Chalcopyrite

18. Galena

19. Calcite

20. Gypsum

Mineral Guide

Documents

Transcript of Mineral Guide