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Conversations with the Earth Tom Burbine tburbine@framingham.edu. Quiz on Thursday. You can bring in your hand-written mineral sheets. Cation – positively charged ion Anion – negatively charged ion NaCl – Na + is the cation and Cl - is the anion. Mineral classes that we studied .
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Conversations with the EarthTom Burbinetburbine@framingham.edu
Quiz on Thursday • You can bring in your hand-written mineral sheets
Cation – positively charged ion • Anion – negatively charged ion • NaCl – Na+ is the cation and Cl- is the anion
Mineral classes that we studied • Silicates – contain silicon and oxygen • Carbonates – contain (CO3)2− • Sulfates – contain (SO4)2− • Halites – contain F−, Cl−, Br−, or I− as an anion • Oxides - contain oxygen (O2-) that is bonded to one or more metal ions • Sulfides - contain sulfur (S2−) as the anion • Native elements
Graphite • C • Used in pencils • Greasy feel • Grey streak • Electrical conductor
Olivine • (Mg,Fe)2SiO4 • Green, no cleavage • Olivine and high pressure structural variants make up over 50% of the Earth's upper mantle
Biotite • K(Mg,Fe)3AlSi3O10(F,OH)2 • Sheets • Dark color
Galena • PbS • Cubes • Gray streak • Lead ore
Pyrite • FeS2 • Hardness 6 to 6.5 • Gray streak • Can form cubes • Ore for sulfur
Hematite • Fe2O3 • Reddish streak • Metallic or non-metallic luster
Fluorite • CaF2 • Hardness of 4 • Colorless, purple, green, yellow
Halite • NaCl • Salt • Cubes • Results from the drying up of lake beds or seas
Muscovite • KAl2(AlSi3O10)(F,OH) • Comes in sheets • Clear
Talc • Mg3Si4O10(OH)2 • In loose form, it is known as talcum powder • Most tailor's chalk is talc
Amphibole • Ca2(Mg,Fe,Al)5(Al,Si)8O22(OH)2 • Prisms with cleavage at 56o and 124o • Fibrous varieties used as fireproof clothing
Calcite • CaCO3 • Single calcite crystals display an optical property called double refraction
Garnet • Mg3Al2(SiO4)3 • Hardness of 7 • Forms dodecahedrons • Gemstone
Gypsum • CaSO4·2H2O • Hardness of 2 • Colorless, white, or gray
Dolomite • CaMg(CO3)2 • Fizzes in dilute HCl if powdered
Quartz • SiO2 • second most abundant mineral in the Earth's continental crust
Chalcopyrite • CuFeS2 • Hardness of 3.5-4 • Dark gray streak • source of ignition in early firearms
Chlorite • (Mg,Fe)3(Si,Al)4O10 • Very soft • The powder generated by scratching is green. • Feels oily when rubbed between the fingers.
Sphalerite • (Zn,Fe)S • Smells like rotten eggs if scratched/powdered • Ore of zinc
Plagioclase feldspar • CaAl2Si2O8 • Has striations
Magnetite • Fe3O4 • most magnetic of all the naturally occurring minerals on Earth
Augite (pyroxene) • (Ca,Na)(Mg,Fe,Al)(Si,Al)2O6 • Cleavages at nearly right angles
Potassium feldspar (Orthoclase) • KAlSi3O8 • Usually pinkish
Kaolinite • Al2Si2O5(OH)4 • soft, earthy, usually white mineral • Produced by weathering of feldspars • main component in porcelain