1. Physical Geology Laboratory Tuesday Tom Burbine tomburbine@astro.umass.edu

2. Mineral A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystal structure 4,000 known minerals –Of these, perhaps 100 can be called "common", –50 are "occasional“ –rest are "rare" to "extremely rare".

3. Is ice a mineral?

4. Yes, as long as it was made inorganically

5. Crystal Structure Crystalline structure - orderly three-dimensional arrangement of atoms or molecules Forms crystals

6. Color Usually the most noticeable property Sometimes minerals can have a wide variety of colors

7. Clarity Transparent – clear Translucent – foggy Opaque – light doesn’t travel through

8. Crystal Form Perfectly grown crystals can have a perfect crystal form (e.g., cube, pyramid, prism)

9. Luster How light reflects from a mineral Metallic luster – reflects like a metal Nonmetallic luster – doesn’t reflect like a mineral –Vitreous – like a glossy photograph –Waxy – like the luster of a candle –Satiny – like the luster of satin –Earthy – like dry soil –Greasy – like the luster of grease –Porcelaneous – like the luster of porcelain

10. Streak Color of a substance as a fine powder A mineral is scratched on a streak plate

11. Hardness Mohs Hardness scale 1-10 scale Hard minerals- can scratch glass Soft minerals – –can’t scratch glass

12. Cleavage Cleavage – tendency of some minerals to break along flat, parallel surfaces Cleavage planes are parallel surfaces of weak chemical bonding Fracture is a break in a mineral does not occur along a cleavage plane

13. Tenacity Tenacity - resists breakage Brittle – shatters like glass Malleable – like clay Elastic – like a plastic comb Sectile – carved with a knife

14. Reaction with acid Fizzes with cool, dilute hydrochloric acid Carbonate minerals (minerals with CO 3 ) Calcite readily fizzes Dolomite will only fizz if powdered

15. Striations Straight, hairline grooves on the cleavage surfaces Plagioclase feldspar has striations

16. Magnetism Magnetic Magnetite is magnetic

17. Specific gravity Density of a substance divided by the density of water E.g., quartz has a specific gravity of 2.65

18. Any Questions?