Understanding Mineral Properties and Moh’s Scale of Hardness: A Comprehensive Guide

1. Warm Up 11-12-13 • What are the 5 properties of a mineral? • What are two different types of tests you can do on a mineral to see what mineral it is?

2. Rocks and Minerals

3. Moh’s Scale of Hardness Moh’s Scale of Hardness was made by a man named Friedrich Moh. It measures to see how much a mineral can be scratched. It goes from talc to diamond.

4. Talc • softest on Moh’s scale • light to dark green, brown, white • monoclinic or triclinic • fractures in an uneven way • Streak is white to pearl green • its luster is pearly or wax-like • can be used as talcum powder or baby powder.

5. Gypsum • number 2 on the scale of hardness • colorless to white; may be yellow, tan, blue, pink, brown, reddish brown or gray due to impurities • luster is vitreous to silky, pearly, or waxy • streak is white • prismatic • can be used as drywall

6. Calcite • colorless or white, also gray, yellow, green • conchoidal • number 3 on the scale • streak is white • trigonal hexagon scalenohedral • vitreous to pearly on cleavage surfaces

7. Fluorite • colorless, white, purple, blue, green, yellow, orange, red, pink, brown, bluish black; commonly zoned • isometric • subconchoidal to uneven • vitreous • number 4 on scale • streak is white

8. Apatite • transparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown. • hexagonal • streak is white • conchoidal to uneven

9. Feldspar • pink, white, gray, brown • vitreous • streak is white • is number 6 on the scale • triclinic or monoclinic

10. Quartz • from colorless to black, through various colors • trigonal trapezohedral and hexagonal • vitreous – waxy to dull when massive • streak is white • number 7 in scale

11. Topaz • colorless (if no impurities), blue, brown, orange, gray, yellow, green, pink and reddish pink • Orthorhombic • vitreous • streak is white • number 8 on the scale

12. Corundum • colorless, gray, brown; pink to pigeon-blood-red, orange, yellow, green, blue to cornflower blue, violet; may be color zoned, asteriated mainly grey and brown • trigonal • number 9 on scale • vitreous • streak is white

13. Diamond!!!! • typically yellow, brown or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple and red. • octahedral • hardest mineral • no color streak • the only thing that can scratch diamond is diamond • admantine