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Minerals

Minerals. Ch. 9. 9.1 What is a mineral?. Minerals Inorganic A. Kinds of minerals B. Silicate minerals Nonsilicated minerals C. Crystalline structure The crystalline structure of silicate minerals Isoloated tetrahedral silicates and rign silicates

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Minerals

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  1. Minerals Ch. 9

  2. 9.1 What is a mineral? • Minerals • Inorganic • A. Kinds of minerals • B. Silicate minerals • Nonsilicated minerals • C. Crystalline structure • The crystalline structure of silicate minerals • Isoloated tetrahedral silicates and rign silicates • Single-chain silicates, double-chain silicates, sheet silicates, and framework silicates

  3. Mineral • Ex. Ruby, gold nugget, salt • Definition :A natural, inorganic, crystalline solid • Natural means not man made • Inorganic means not made up of any living pieces dead or alive • Crystalline solid means crystal form.

  4. How to tell if something is a mineral. • 4 basic questions – if yes to all 4 it is a mineral. • Is it inorganic? – no carbon • Occur naturally? – not man made • Solid in crystalline form? • Definite chemical composition – element or compound

  5. A. Kinds of Minerals • There are over 3,000 different minerals. • Fewer than 20 are common • Common minerals are rock forming minerals. They form rocks on the earths crust. • 90% of earth’s crust made up of 10 common minerals

  6. 10 most common rock minerals • Quartz • Orthoclase • Plagioclase • Muscovite • Biotite • Calcite • Dolomite • Halite • Gypsum • ferromagnesian

  7. 2 groups of minerals • 1. Silicate • 2. Nonsilicate

  8. Silicate minerals • 96 % of earths crust is made of silicate minerals. • Feldspar and quartz make up 50% of crust • Silicate minerals – contain atoms of silicon(Si) and Oxygen (O). • Quartz – only silicon and oxygen • Feldspars – most common, types depend on metal mixed with Si and O2 • Orthoclase – K • Plagioclase – Na or calcium or both • Ferromagnesian – Fe and Mg • (olivines, pyroxenes, amphiboles, biotite)

  9. Nonsilicate Minerals • 4% of crust • Do not contain silicon • 6 groups • 1. carbonates – contains carbonate group dolomite and calcite • 2. Halides – chlorine or fluorine w/Na, K, Ca halite • fluorite • 3. Native elements – uncombined Ag, Cu • 4. Oxides – O2 corundum, hematite • 5. Sulfates – sulfate gypsum, anhydrite • 6. sulfides – sulfur galena, pyrite

  10. Crystalline structure • Natural solid with a geometric pattern • Use of xrays to identify • A. Isoloated tetrahedral silicates and ring silicates • B. Single-chain silicates, double-chain silicates, sheet silicates, and framework silicates

  11. The crystalline structure of silicate minerals • Silicon-oxygen tetrahedron – basic building blocks of 4 O2 in a pyramid and 1 silicon

  12. Isolated tetrahedral silicates and ring silicates • The tetrahedral bonds with other elements • Rings are formed when tetrahedral bind in 3’s

  13. Single-chain silicates, double-chain silicates, sheet silicates, and framework silicates • Single chain • Tetrahedron bonded to 2 others by shared O2 • Pyroxenes • 2 single chains bond together • Amphiboles • Sheet – sharing 3 O2 with other tetra, 4th with K or Al • Micas • Framework - tetra bonds with 4 other tetra • quartz

  14. 9.2 Identifying Minerals • A. Characteristics of minerals • 1. color • 2. Luster • 3. Streak • 4. Cleavage and fracture • 5. Hardness • 6. Crystal shape • 7. Density • B. special properties of minerals • 1. magnetism • 2. fluorescence and phosphorescence • 3. double refraction • 4. radioactivity

  15. A. Characteristics of minerals • 1. color • 2. Luster • 3. Streak • 4. Cleavage and fracture • 5. Hardness • 6. Crystal shape • 7. Density

  16. 1. color • Sulfur – bright yellow • Azurite – deep blue • Cinnabar – red • Serpentine – green • little mineral can be a lot of color • Ruby • Sapphire • Quartz • Iron pyrite changes gold to yellow with weathering

  17. 2. Luster • Light reflected from the surface • 1. Metallic luster - shiny • 2. Nonmetalic luster – glassy, waxy, pearly • Dull (earthy) luster – lacks shine

  18. 3. Streak • Mineral in powder form • Draw (rub) on tile • Dark is usually metal • Nonmetals – colorless or light

  19. 4. Cleavage and fracture • Ability to cut along flat surface • Based on weak bonds • Fracture – break into irregular pieces • Types: • 1. Uneven or irregular - rough • 2. Splintery or fibrous – broken wood • 3. Conchoidal - curved

  20. 5. Hardness • Ability to Resist scratching • Mohs hardness scale • 1-10 • 1 soft • 10 hardest • Scratch test • Strength of bonds

  21. Mohs hardness scale • HardnessMineralAssociations and Uses • 1TalcTalcum powder. • 2GypsumPlaster of paris. Gypsum is formed when seawater evaporates from the Earth’s surface. • 3CalciteLimestone and most shells contain calcite. • 4FluoriteFluorine in fluorite prevents tooth decay. • 5ApatiteWhen you are hungry you have a big "appetite". • 6OrthoclaseOrthoclase is a feldspar, and in German, "feld" means "field". • 7Quartz  • 8TopazThe November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8. • 9CorundumSapphire and ruby are varieties of corundum. Twice as hard as topaz. • 10DiamondUsed in jewelry and cutting tools. Four times as hard as corundum.

  22. Hardness of some other items: • 2.5Fingernail • 2.5–3Gold, Silver • 3Copper penny • 4-4.5Platinum • 4-5Iron • 5.5Knife blade • 6-7Glass • 6.5Iron pyrite • 7+Hardened steel file

  23. 6. Crystal shape • Minerals always combine with the same geometric pattern • 1. isometric or cubic system • 2. triclinic system • 3. Hexagonal system • 4. orthorhombic system • 5. monoclinic system • 6. tetragonal system

  24. 7. Density • D = m/v • Will feel heavier – lead, gold

  25. B. special properties of minerals • 1. magnetism • 2. fluorescence and phosphorescence • 3. double refraction • 4. radioactivity

  26. 1. magnetism • Magnetic will attract iron • Ex. Magnetite is most common • Lodestone is a form of magnetite • Acts like a bar magnet with poles (N&S) • Used as compass by early navigation

  27. 2. fluorescence and phosphorescence • Ability to glow under UV light • Ex. Calcite white appears >red under UV light • Absorbs UV and produces visible light • Willemite light brown > green under UV • Phos. – glows after UV light off

  28. 3. double refraction • Refraction – light rays bending as pass through crystals of calcite produces double image

  29. 4. radioactivity • Unstable e- arrangement or proton and neutrons in nucleus • Ex. U or Ra • U – pitchlende, carnotite, uraninite, autotite

  30. Shelby Gem Stone Factory

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