BAESI: Minerals November 19, 2011 Ellen Metzger

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Acknowledgements  The BAESI Saturday workshop program is made possible by a grant from Chevron.  Geologic maps of California supplied by the Northern California Geological Society and the American Association of Petroleum Geologists Foundation.

 What is a mineral?

What is a Mineral? A mineral is a naturally-occurring, inorganic solid with a definite (but generally not fixed) chemical composition and an orderly internal arrangement of atoms (crystalline). Examples of chemical formulas for minerals: Quartz: SiO 2 Pyrite: FeS 2

Crystalline Halite - NaCl Definite chemical composition Orderly arrangement of atoms

Both are crystalline Virtual Geology Museum at Cochise College – Copyright-free phtos

"Walking into either of these caves is like stepping into a gigantic geode," said Richard D. Fisher, an American consultant with the mining company to develop the discoveries as tourist attractions. Fisher said that most people can endure only a few minutes in the caves due to their high temperatures.

Mineral Identification  What properties can be used to identify minerals?  What do you observe?

Physical properties used to identify minerals  Color  Streak  Luster  Hardness  Cleavage/fracture  Specific gravity (“heft’)  Reaction with dilute HCl (or vinegar)  Magnetism  Crystal habit or form

Color All of these are quartz.

Two Forms of Hematite: Same Streak

Luster  Pyrite: Metallic Luster  Halite: Nonmetallic Luster Shiny does not equal metallic.

Moh’s Scale of Hardness 1 = Talc 2 = Gypsum 3 = Calcite 4 = Fluorite 5 = Apatite 6 = Orthoclase 7 = Quartz 8 = Topaz 9 = Corundum 10 = Diamond Hardness of everyday objects Fingernail: 2.5 Penny ~ 3.5 Glass and a steel nail: 5.5 and

Examples of Cleavage Look for signs of breakage: “steps” on mineral surfaces

Fracture: Irregular Breakage Quartz has conchoidal (curving fracture)

California’s Unique Rocks and Minerals  Blueschist  Graywacke  Serpentinite

California’s Non-fuel Mineral Production, 2007

California’s Mineral Resources  What is our state gem?  Our state mineral?  Our state rock?