Presentation on theme: "Rules & Suggestions TEAM OF 2 TEAMS MAY BRING: MAGNIFYING GLASS 1 PUBLISHED FIELD GUIDE 3-RING BINDER Make review sheets: Examples: formulas for all."— Presentation transcript:
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 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.
VISITATIONS SEE 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 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
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.
HYDROTHERMAL VEIN DEPOSITS PYRITEFluorite (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.
STREAK : The color of the powered mineral Mineral:PyroxeneHematiteLimoniteMagnetiteAmphibole Streak color: ColorlessBrick red Yellow brown BlackColorless
MOHS SCALE OF HARDNESS
IDENTIFYING MINERALS LUSTER Metallic or Non metallic Non-Metallic Vitreous Adamantine pearly resinous silky waxy greasy dull
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 GoldCopper
OTHER PROPERTIES BIREFRINGENCE : Difference between highest and lowest index of refraction. A high degree causes double refraction.
Reaction to Acid Ca Co 3 + 2H --- Ca + H 2 O + CO 2 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. QuartzTourmaline
CRYSTALS ARRANGEMENT OF ATOMS
HABIT THE CHARACTERISTIC APPEARANCE OF A CRYSTAL. Terms to describe crystal habit are: Prismatic : BerylPrismatic Terminated Prisms Quartz in Barite
FRACTURE No Cleavage planes Hackly Conchoidal irregular
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 planesSphalerite
What Cleavage Type? MineralMineral CleavageCleavage
Scientific Classification of Mineral Groups There are eight major classes according to chemical composition 1.Elements 2.Sulfides 3.Oxides and Hydroxides 4.Halides 5.NitratesCarbonatesBorates 6.Sulfates 7.Phosphates 8.Silicates
NATIVE ELEMENTS Six in this Group Graphite, silver, gold, copper, sulfur, diamond. Occur in nature in uncombined form. CopperSilverGold Gold METALS: SilverCopper
Non Metals Native Elements Graphite, 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!
SULFIDES Copper Iron Sulfides BORNITECHALCOPYRITE
SULFIDES PYRITEGALENASPHALERITE Iron sulfideLead sulfideZinc Sulfide
OXIDE CLASS Five in this group Includes Oxides and Hydroxides 45% of Earths 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
HALIDES (Two in this group) Commonly found as a metal and a halogen (the principle anion) Halite (NaCl)Fluorite (CaF 2 )
CARBONATES Contain one or more metallic elements plus the carbonate radical (CO 3 ) 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(CO 3 ) 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, SO 4 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
SULFATES Many have economic Importance BARITE BaSO 4 CELESTITE, SrSO 4
GYPSUM: several variety names. SeleniteSatin SparAlabastor
PHOSPHATES One or more metal elements with the phosphate radical, PO 4 Apatite in Calcite
SILICATES SIO 4 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. TectosilicatesFramework Silicates 2. PhyllosilicatesSheer Silicates 3. InosilicatesChain Silicates 4. CyclosilicatesRing Silicates 5. SorosilicatesDouble Tetrahedral 6. NeosilicatesIndependent Tetrahedral
TECTOSILICATES SIO 2 GREEK FOR FRAMEWORK! Every O atom is bonded to two Si atoms as in Crystal QuartzOpal
Quartz Family Rose QuartzAgateAmethyst ChalcedonyJasperMilky Quartz Citrine Quartz
TECTOSILICATES SIO 2 + FELDSPARS A negative charge is created, which introduces the positive metals of K, Na or Ca. Sodalite
PHYLLOSILICATES Clay Group Greek for leaf, sheet silicates (have one cleavage direction parallel to layers) KAOLINITE TALC
INOSILICATES Inosilicates: the chain structure, double or single. Amphibole Group: Wedge shaped prismatic cleavage planes; longer, slender crystals. HornblendeTremoliteRhodonite
INOSILICATES, Pyroxene Group Prismatic cleavage planes give it a square or rectangular cross section. Shorter and more blocky crystals as compared to amphiboles. AUGITE
CYCLOSILICATES Beryl 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)
Fine Grained Igneous Rocks Aphanitic Texture (Extrusive) RhyoliteAndesiteBasalt FelsicIntermediateMafic
Glassy or Frothy Texture PumiceObsidianScoria FrothyGlassyFrothy FelsicFelsicMafic
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 rhyolitePorphyritic 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 ROCKS AND FOSSILS Fossiliferous Limestone Shale with Fossils Coal with Fossils
CLASTIC ROCKS Classified by texture or grain size ConglomerateBreccia Gravel size range (over 2mm) Rounded FragmentsAngular Fragments
Clastic Rocks: Sand size Range (1/16 mm to 2mm) SandstoneArkose Mostly quartzAt least 25% feldspar
Clastic rocks: Clay size particles less than 1/256 mm Shale: laminated layers of quartz and clay minerals
Coal Formation »Peat exposed to heat and pressure from burial beneath other sediments becomes compressed and chemically changes into low grade coals such as this lignite. Lignite typically transforms to bituminous coal as it is compressed further and heated to between 100 and 200°C. This drives much of the water and other volatiles from the coal. Longer exposure to elevated temperature will further drive volatiles from the coal, and drive chemical reactions that produce anthracite.
The carbon content of the coal rises as it is compressed further and the moisture content falls.
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 Limestones When Minerals fall out of solution CrystallineOolitic TravertineDolomite limestonelimestone 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 ROCKS TYPES 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!