Rules & Suggestions TEAM OF 2 TEAMS MAY BRING: MAGNIFYING GLASS 1 PUBLISHED FIELD GUIDE 3-RING...
Transcript of Rules & Suggestions TEAM OF 2 TEAMS MAY BRING: MAGNIFYING GLASS 1 PUBLISHED FIELD GUIDE 3-RING...
Rules & Suggestions• TEAM OF 2
• TEAMS MAY BRING:
MAGNIFYING GLASS
1 PUBLISHED FIELD GUIDE
3-RING BINDER
Make review sheets: Examples: formulas for all minerals, physical properties of minerals, uses for minerals
• REFER TO THE NATIONAL 2013 LIST
Official 2012 Rocks and Minerals List (PDF)
TEAM PREPARATION
• Meet once a week, give students a course outline; what you are going to study each week. Give them a short assignment to work on for the next week.
• Each student composes a notebook. 12X12X3
• Give a station whenever possible; time practice, and practice using notebooks.
VISITATIONSSEE SPECIMEN
• VISIT COLLEGES, MINERAL MUSEUMS TO SEE DIFFERENT SPECIMEN.
• VISIT ROCK AND MINERAL SHOWS WITH STUDENTS; GET THEM HOOKED!
• SEEK OUT SPECIALISTS, SOME OUR JUST OLD ROCK HOUNDS!
• GO ON YOUR OWN ROCK & MINERAL HUNT!
ELEMENTS!!
• Periodic Table: Occurrence in minerals• http://www.mii.org/periodic/MiiPeriodicChart.htm
Structure of the Table (metals, nonmetals)
Elements & Compounds
Formulas and Symbols
Common Radicals
WHAT IS A MINERAL?
• Inorganic solid
• Naturally occurring
• Homogeneous
• Definite physical properties
• Semi- Definite composition
• Crystalline Structure
Why Minerals are important?
SIX BASIC TYPES OF MINERAL ENVIRONMENTS
• IGNEOUS ENVIRONMENTS (PLUTONIC AND VOLCANIC)
• METAMORPHIC ENVIRONMENTS• SEDIMENTARY ENVIRONMENTS• HYDROTHERMAL REPLACEMENT
DEPOSITS• HYDROTHERMAL VEINS• SECONDARY REPLACEMENT DEPOSITS
PLUTONIC IGNEOUS ENVIRONMENT
PEGMATIC ENVIRONMENTS• Pegmatite minerals include apatite, biotite,
corundum, feldspar, muscovite, quartz, pyroxene, topaz, tourmaline.
Metamorphic Environments
Some Minerals only form under great heat and
pressure and these minerals can become unstable when conditions
change. When stability is affected , existing rocks undergo
change and new minerals can form.
Sedimentary Environments• Placer Deposits: Heavy stable minerals
remain behind when rocks disintegrate and these remains are carried by moving water. GOLD!
Hydrothermal Replacement Minerals
• Hydrothermal water, especially acid water, is effective at removing, changing and replacing minerals in the surrounding country rock.
Azurite is a secondary
copper mineral and develops in the zone of alteration in hydro-
thermal replacement deposits, where it
commonly occurs with malachite.
Vein Deposits
HYDROTHERMAL VEIN DEPOSITS• PYRITE Fluorite (formed
in Ill when hot water flowed through cracks in
limestone.
Secondary Replacement Deposits• Develop from primary minerals in the
original deposit.
• Chalcopyrite alters readily to Bornite!
IDENTIFYING MINERALS• COLOR (LEAST RELIABLE)
• STREAK: Color of Powdered mineral
• HARDNESS
• LUSTER
• SPECIFIC GRAVITY
• TENACITY
• CLEAVAGE/FRACTURE
• CYRSTAL SYSTEM
• OTHER PROPERTIES
COLOR OF MINERAL
• Visible light spectrum radiation reflected from a mineral.
Amethyst
Amazonite
LepidoliteAzurite & Malachite
STREAK : The color of the powered mineral
Mineral: Pyroxene Hematite Limonite Magnetite Amphibole
Streak color:
Colorless Brick red Yellow brown
Black Colorless
MOH’S SCALE OF HARDNESS
IDENTIFYING MINERALSLUSTER
Metallic or Non metallic• Non-Metallic
VitreousAdamantinepearlyresinoussilkywaxygreasydull
SPECIFIC GRAVITY• How many more times a mineral weighs
compared to an equal amount of water.
• Specific Gravity =
Weight of sample in air/ Weight of equal
volume of water
• Specific Gravity =
Weight of sample in
air / loss of weight in
water
TENACITY• How tough a mineral is, how easily it will
break or split
* elastic: Can be bent and then resume original shape (mica)
* ductile: Pulled to make thin threads.
(gold)
* malleable: Cut into thin sheets (copper)
* Sectile: Can be cut by blade into
shavings ( Gypsum)
* Friable: crumbles easily
Malleable and Ductile
Gold Copper
OTHER PROPERTIES• BIREFRINGENCE : Difference between
highest and lowest index of refraction. A high degree causes double refraction.
Reaction to Acid• Ca Co3 + 2H --- Ca + H2O + CO2
• Al Carbonate Minerals, Limestones and marble
Magnetic Properties• Occurs when there is an imbalance in
structural arrangement of the Fe atoms. The Ferrous ion is Fe +2 and the Ferric ion is Fe +3. When the electrons move from the Ferrous to the Ferric ions, a magnetic field is created.
Fluorescent Minerals• The changing of invisible light or X-ray
beams to visible light. If light continues after source is turned off, the mineral is phosphorescence.
Piezoelectric Properties• Temperature or pressure changes cause some
minerals to acquire an electric charge when warmed, cooled or pressed.
Quartz Tourmaline
CRYSTALSARRANGEMENT OF ATOMS
HABIT• THE CHARACTERISTIC APPEARANCE
OF A CRYSTAL. Terms to describe crystal habit are:
• Prismatic : Beryl Prismatic Terminated Prisms Quartz in Barite
Habit• Dendritic Copper Reniform
(kidney- shaped) Hematite
Habit DescriptionTWINNING
• Contact Twin Penetration Twin
Quartz Staurolite
STRIATIONS, PRODUCTOF THE HABIT
FRACTURENo Cleavage planes
• Hackly
• Conchoidal
• irregular
Cleavage Examples
CLEAVAGE
• BASAL: 1 direction or planes (layers)– Muscovite, talc
• Prismatic: 2 directions at rt angles: Barite
• Cubic: 3 directions at right angles: Halite
• Rhombohedral: 3 directions: calcite
• Octahedral: 4 planes (pyramid) Fluorite
• Dodecahedral: 6 planes Sphalerite
What Cleavage Type?
• Mineral Mineral
• Cleavage Cleavage
Scientific Classification of Mineral Groups
• There are eight major classes according to chemical composition1. Elements
2. Sulfides
3. Oxides and Hydroxides
4. Halides
5. Nitrates Carbonates Borates
6. Sulfates
7. Phosphates
8. Silicates
NATIVE ELEMENTSSix in this Group
• Graphite, silver, gold, copper, sulfur, diamond. Occur in nature in uncombined form.
• Copper Silver Gold
• Gold
• METALS:
• Silver Copper
Non Metals Native ElementsGraphite, Diamond & Sulfur
Sulfide class• Metals with sulfur
• Economically important class of minerals
• Major ores of important metals (Cu, Pb, Ag, Fe, Zn)
• Most are metallic, opaque, sectile, soft to average hardness, and high densities, and igneous in origin
• There are five in this group
• All give streaks!
SULFIDESCopper Iron Sulfides
BORNITE CHALCOPYRITE
SULFIDESPYRITE GALENA SPHALERITEIron sulfide Lead sulfide Zinc Sulfide
OXIDE CLASSFive in this group
• Includes Oxides and Hydroxides
• 45% of Earth’s crust is Oxygen, very diverse group
• Quartz (SiO2) could be considered an oxide except for the covalent silicon oxygen bonds.
• The OH group has a -1, where as the single oxygen has a -2 charge
OXIDES• Corundum Hematite Magnetite
Aluminum Oxide Iron Oxide Iron Oxide
HYDROXIDES• Bauxite Goethite
Aluminum Hydroxide Iron Hydroxide
HALIDES (Two in this group)• Commonly found as a metal and a
halogen (the principle anion)
Halite (NaCl) Fluorite (CaF2)
CARBONATES
• Contain one or more metallic elements plus the carbonate radical (CO3)
• Soft, brittle, transparent, effervesce in HCl, soft with good to perfect cleavage
• Tend to originate in sedimentary and oxidizing environments
• Three major types are calcites, aragonites and dolomites
• Aragonite, a polymorph of calcite
Dolomite, CaMg(CO3)2
• Azurite and Malachite: Copper Carbonates
• Malachite represents a later stage of oxidation an replaces azurite.
BORATES, More complex than Carbonates
Metal Plus Borate Radical• Ulexite, Evaporite Deposit
SULFATE CLASS
• One or more metallic elements plus the Sulfate radical, SO4
• Transparent to translucent, soft, most are heavy and light colored
• Includes Barite, Celestite, and Gypsum
• Variety of environments, Often in oxidation zones and evaporite deposits
SULFATESMany have economic Importance
• BARITE BaSO4 CELESTITE, SrSO4
• GYPSUM: several variety names.
• Selenite Satin Spar Alabastor
PHOSPHATES One or more metal elements with the phosphate
radical, PO4
• Apatite in Calcite
SILICATESSIO4
• 40% OF COMMON MINERALS ARE SILICATES!
SIX CLASSES OF SILICATES Low SG, Harder than most minerals
• Based on the interactive formations of the tetrahedrons
1. Tectosilicates Framework Silicates
2. Phyllosilicates Sheer Silicates
3. Inosilicates Chain Silicates
4. Cyclosilicates Ring Silicates
5. Sorosilicates Double Tetrahedral
6. Neosilicates Independent Tetrahedral
TECTOSILICATESSIO2
• GREEK FOR FRAMEWORK! Every
O atom is bonded to two Si atoms as in
Crystal Quartz Opal
Quartz Family• Rose Quartz Agate Amethyst
• Chalcedony Jasper Milky Quartz
• Citrine Quartz
TECTOSILICATESSIO2 + FELDSPARS
• A negative charge is created, which introduces the positive metals of K, Na or Ca.
• Sodalite
PHYLLOSILICATESClay Group
• Greek for leaf, sheet
• silicates (have one
• cleavage direction parallel to layers)KAOLINITE
TALC
Phyllosilicates (Micas)MUSCOVITE MICA
Lepidolite
INOSILICATES• Inosilicates: the chain structure,
double or single.
Amphibole Group: Wedge shaped prismatic cleavage planes; longer, slender crystals.
Hornblende Tremolite Rhodonite
INOSILICATES,Pyroxene Group
• Prismatic cleavage planes give it a square or rectangular cross section. Shorter and more blocky crystals as compared to amphiboles.
AUGITE
CYCLOSILICATESBeryl and Tourmaline
• Greek for ring, known as the ring Silicates!The symmetry of the rings gives these two minerals the hexagonal shape!
SOROSILICATES• Have two tetrahedrons linked by one
oxygen giving it an hour glass shape
Epidote: Metamorphic Environment
Neosilicates• Isolated Tetrahedron: Garnet, Olivine, Topaz,
Staurolite (short, blocky, square crystals)
Greek for Island, share no oxygen ions.
Olivine Garnet TOPAZ
Staurolite
IGNEOUS ROCKS
• CLASSIFIED BY TEXTURE AND MINERAL COMPOSITION
• REFERRED TO AS INTRUSIVE(PLUTONIC) OR EXTRUSIVE (VOLCANIC)
• FORM FROM FELSIC MINERALS (LIGHT COLORED, ACIDIC) OR MAFIC MINERALS (DARK COLORED, BASIC)
TEXTURE OF IGNEOUS ROCKS• PHANERITIC: Intrusive, coarse grained.
• Granite Diorite Gabbro
Felsic Intermediate Mafic
Fine Grained Igneous Rocks
• Aphanitic Texture (Extrusive)
• Rhyolite Andesite Basalt
• Felsic Intermediate Mafic
Glassy or Frothy Texture
• Pumice Obsidian ScoriaFrothy Glassy Frothy
Felsic Felsic Mafic
PEGMATITE• Abnormally large crystals. Unlike other igneous rocks
that develop from the molten state, pegmatites grow from aqueous solutions. Pegmatites can produce large crystals in a short period of time. (geologically)
Porphyritic Texture
• Two distinct crystal sizes produced by different cooling of the liquid rock. The large crystals are called phenocrysts.
• Porphyritic rhyolite Porphyritic basalt
SEDIMENTARY ROCKS• CLASSIFIED AS CLASTIC OR
NONCLASTIC.
• CLASTIC: SEDIMENTS CEMENTED OR COMPACTED TOGETHER
• NONCLASTIC: ORGANIC, OR CHEMICALPRECIPITATES.
Sedimentary Rock Features• Graded Bedding and Cross Bedding
Sedimentary Rocks: Ripple Marks and Mudcracks
SEDIMENTARY ROCKSAND FOSSILS
Fossiliferous LimestoneShale with Fossils
Coal with Fossils
SORTING OF SEDIMENTS
ORGANIC ORIGINBio-chemical
• Coquina Chalk Fossiliferouslimestone
CLASTIC ROCKSClassified by texture or grain size
• Conglomerate BrecciaGravel size range (over 2mm)
Rounded Fragments Angular Fragments
Clastic Rocks: Sand size Range (1/16 mm to 2mm)
• Sandstone Arkose
• Mostly quartz At least 25% feldspar
Clastic rocks: Clay size particlesless than 1/256 mm
• Shale: laminated layers of quartz and clay minerals
Coal Formation
The carbon content of the coal rises as it is compressed further and the moisture content falls.
Organic Origin: Coal
• Lignite
• Bituminous
• Anthracite
Organic Origin: Diatomite• Diatomaceous earth, the pinkish white outcrop shown
above (near Lovelock, Nevada), is a mineral of plant origin. It represents the accumulation of an enormous number of fossil diatoms (single-celled plants Diatomite has several unique characteristics. Because of its lightness, porosity, and its honeycombed structure, it's an ideal filtering medium.
Chemical LimestonesWhen Minerals fall out of solution
• Crystalline Oolitic Travertine Dolomite
limestone limestone Rock
AGENTS OF METAMORPHISM
• HEAT: Geothermal gradient: due to radioactive decay and intrusions of hot magma.
• Pressure: Burial Pressure, Tectonic Pressure, or fault zones pressure.
• Chemical fluids: hydrothermal solutions
HOW ROCKS CHANGE
• TEXTURE:
Compaction: more dense, less porous
* MINERALOGY Recrystallization: Growth of new crystals
from Minerals present,
often forming foliation.
METAMORPHIC TEXTURES
• SCHISTOSITY: large mica flakes
• Slaty cleavage: alignment of very fine grained micas.
• Phyllitic structure: alignment of fine grained micas.
• Gneissic banding: segregation of light and dark minerals into layers.
METAMORPHIC ROCKSTYPES
• CONTACT METAMORPHISM: MAGMA FORCES ITS WAY INTO OVERLYING ROCK, CHANGING THE ROCKS THAT COME IN CONTACT WITH IT. CHANGES ARE LESS DRASTIC AND FOLIATION NOT PRESENT.
• REGIONAL METAMORPHISM: LARGE AREAS OF ROCK UNDERGO INTENSE HEAT AND PRESSURE. (OCCURS DURING MOUNTAING BUILDING PROCESSES) Often foliation!
KINDS OF METAMORPHISM
REGIONAL METAMORPHISM“Barrovian”
• Slate------phyllite-------schist------gneiss
Contact Metamorphism(Not always by contact)
• Marble Quartzite
ROCK CYCLE