Geology Minerals Flashcard
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Talc
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Luster: Dull/Earthy Hardness: 1 Cleavage/Fracture: 1 perfect cleavage Color/Streak:White *soft powders, soapy feel,greesy
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Augite
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Luster:Vitreous/Glassy Hardness:>5.5 Cleavage/Fracture: 2 @ 90 (stair steps) Color/Streak:Black,Dark green/ Gray or green
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Galena
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Luster:Metallic Hardness: 2.5-3.5 Cleavage/Fracture:3 @ 90 (cube) Color/Streak:Gray,Silver/Gray,Black *lead
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Hornblende
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Luster:Vitreous/Glassy Hardness:>5.5 Cleavage/Fracture: 2 @ 60 & 120 Color/Streak:Black,Dark green
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Limonite
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Luster:Dull/Earthy Hardness: 2.5-5 Cleavage/Fracture: no cleavage Color/Streak:Yellow, Brown *looks like rust
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Olivine
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Luster:Glassy grains/sugary Hardness:6.5-7 Cleavage/Fracture: Conchodial fracture Color/Streak:Green,Olive Green/White
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Quartz
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Luster:Vitreous/Glassy Hardness:>5.5 Cleavage/Fracture: Conchondial Fracture Color/Streak:Clear/ White
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Na-Rich Plagioclase Feldspar
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Luster:Vitreous/Pearly Hardness: 6 Cleavage/Fracture: 2 planes 2 @ 90 Color/Streak:Light/ White
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Pyrite
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Luster: Metallic Hardness: >5.5 Cleavage/Fracture: 3 planes @ 90 Color/Streak: Gold/Gray,Black,Green
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Calcite
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Luster: Vitreous/Glassy/Pearly Hardness: 3 Cleavage/Fracture: 3 cleavages not at 90 Color/Streak:Variable/White *reacts with acid
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Muscovite
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Luster: Vitreous/Glassy Hardness: 1.5-2.5 Cleavage/Fracture: 1 perfect cleavage Color/Streak: Transparent, light silver or brown/White *elastic flakes/sheets paint additive
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Sphalerite
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Luster:waxy Hardness: 3.5 Cleavage/Fracture: less then 3 cleavages Color/Streak: dark / brown *major zinc ore
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Flourite
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Luster: Glassy, transparent shades to yellow, green, and purple Hardness: 4 Cleavage/Fracture: >3 Color/Streak:Variable/White *confused with quartz
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Potassium Feldspar
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Luster:Pearly, Vitreous/Glassy Hardness: >5.5 Cleavage/Fracture: 2 planes @ 90 Color/Streak: Salmon Pink/ White
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Dolomite
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Luster: Dull/Earthy Hardness: <5.5 Cleavage/Fracture: 3 planes not @ 90 Color/Streak:Tan, Cream/White *reacts with HCL when powdered
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Hematite
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Luster: Dull/Earthy Hardness: 2-2.5 Cleavage/Fracture: Fracture Color/Streak: dark/ Reddish Brown
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Graphite
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Luster: Metallic, Vitreous, Dull/Earthy Hardness: <2.5 Cleavage/Fracture: 1 plane Color/Streak:Gray/Gray or black *feels greasy
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Ca-Rich Plagioclase Feldspar
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Luster:Vitreous/Glassy Hardness: 6 Cleavage/Fracture: 2 planes @ 90 Color/Streak: Dark Gray/White
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Biotite
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Luster: shiny/Glassy Hardness: 2.5-3 Cleavage/Fracture: 1 Perfect cleavage Color/Streak:brown/green *elastic flakes
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Magnetite
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Luster:Metallic Hardness: >5.5 Cleavage/Fracture:Fracture Color/Streak:Black/Black *magnetitic
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Garnet
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Luster: Glassy Hardness: >5.5 Cleavage/Fracture:Fracture Color/Streak:Red,Brown/None *12 sided crystals
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Massive Quartz
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Luster: Vitreous/Glassy Hardness:>5.5 Cleavage/Fracture:Fracture Color/Streak:Variable/None
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Gypsum
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Luster: Earthy, light Hardness: 2-3 Cleavage/Fracture: fracture Color/Streak:White pink/White
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Kaolinite
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Luster:Earthy, powdery appearance Hardness:1-2 Cleavage/Fracture: fracture Color/Streak:White,Cream/White *confused with Talc
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Bauxite
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Luster: Earthy Hardness: <3.5 Cleavage/Fracture:Variable Color/Streak: Tan,Brown,Black/ Varibale *circular shape
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halite (NaCl)
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3 cleavages at 90 2-2.5 colorless, white streak salt products
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Selenite
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3 cleavages not at 90 light color colorless, white streak transparent plaster/wall board
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chert
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Chert has a hardness of 7 and it has a dull luster. It has a streak of colorless streak. conchoidal fracture.
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quartz
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light color colorless/white streak luster/glassy to waxy hardness of 7 no cleavage
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garnet
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dark colored hardness of 7 white streak glassy luster/ redish brown fractures
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orthoclase feldspar
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light color/cream pink hardness of 6 colorless streak 2 cleavage at 90 ceramics
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pyroxene
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2 cleavage at 90 dark colored/greenish black colorless to green streak 5-6 hardness
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amphibole
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2 at 60 degrees dark color, greenish black luster dull to shiny hardness 5-6
