1. Conversations with the Earth Tom Burbine tburbine@framingham.edu

2. Quiz on Thursday You can bring in your hand-written mineral sheets

3. Cation – positively charged ion Anion – negatively charged ion NaCl – Na + is the cation and Cl - is the anion

4. Mineral classes that we studied Silicates – contain silicon and oxygen Carbonates – contain (CO 3 ) 2− Sulfates – contain (SO 4 ) 2− Halites – contain F −, Cl −, Br −, or I − as an anion Oxides - contain oxygen (O 2- ) that is bonded to one or more metal ions Sulfides - contain sulfur (S 2− ) as the anion Native elements

5. Graphite C Used in pencils Greasy feel Grey streak Electrical conductor

6. Olivine (Mg,Fe) 2 SiO 4 Green, no cleavage Olivine and high pressure structural variants make up over 50% of the Earth's upper mantle

7. Biotite K(Mg,Fe) 3 AlSi 3 O 10 (F,OH) 2 Sheets Dark color

8. Galena PbS Cubes Gray streak Lead ore

9. Pyrite FeS 2 Hardness 6 to 6.5 Gray streak Can form cubes Ore for sulfur

10. Hematite Fe 2 O 3 Reddish streak Metallic or non-metallic luster

11. Fluorite CaF 2 Hardness of 4 Colorless, purple, green, yellow

12. Halite NaCl Salt Cubes Results from the drying up of lake beds or seas

13. Muscovite KAl 2 (AlSi 3 O 10 )(F,OH) Comes in sheets Clear

14. Talc Mg 3 Si 4 O 10 (OH) 2 In loose form, it is known as talcum powder Most tailor's chalk is talc

15. Amphibole Ca 2 (Mg,Fe,Al) 5 (Al,Si) 8 O 22 (OH) 2 Prisms with cleavage at 56 o and 124 o Fibrous varieties used as fireproof clothing

16. Calcite CaCO 3 Single calcite crystals display an optical property called double refraction

17. Garnet Mg 3 Al 2 (SiO 4 ) 3 Hardness of 7 Forms dodecahedrons Gemstone

18. Gypsum CaSO 4 ·2H 2 O Hardness of 2 Colorless, white, or gray

19. Dolomite CaMg(CO 3 ) 2 Fizzes in dilute HCl if powdered

20. Quartz SiO 2 second most abundant mineral in the Earth's continental crust

21. Chalcopyrite CuFeS 2 Hardness of 3.5-4 Dark gray streak source of ignition in early firearms

22. Chlorite (Mg,Fe) 3 (Si,Al) 4 O 10 Very soft The powder generated by scratching is green. Feels oily when rubbed between the fingers.

23. Sphalerite (Zn,Fe)S Smells like rotten eggs if scratched/powdered Ore of zinc

24. Plagioclase feldspar CaAl 2 Si 2 O 8 Has striations

25. Magnetite Fe 3 O 4 most magnetic of all the naturally occurring minerals on Earth

26. Augite (pyroxene) (Ca,Na)(Mg,Fe,Al)(Si,Al) 2 O 6 Cleavages at nearly right angles

27. Potassium feldspar (Orthoclase) KAlSi 3 O 8 Usually pinkish

28. Kaolinite Al 2 Si 2 O 5 (OH) 4 soft, earthy, usually white mineral Produced by weathering of feldspars main component in porcelain

29. Any Questions?