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. 1.Is it inorganic? – no carbon 2.Occur naturally? – not man made 3.Solid in crystalline form? 4.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, 4 th 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