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?

Mineral MineralCleavage Cleavage

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