1. N. Lindsley-Griffin, 1999 Quartz Even when the crystals are different sizes, angles between equivalent faces are the same For different minerals, angles are different. 3 3 1 1 22 4 4 Crystal Interfacial Angles

2. N.Lindsley-Griffin, 1999 Habit Habit - distinctive shape of the way the mineral commonly (habitually) appears Concentric shells -- malachite

3. N. Lindsley-Griffin, 1998 Habit

4. Crystal shape and Habit result from internal atomic structure N. Lindsley-Griffin, 1998

5. Cleavage - tendency to break along planes of weak bonds N.Lindsley-Griffin, 1998

6. Mica cleaves along planes of the weakest bonds N. Lindsley-Griffin, 1998

7. Fracture describes how a mineral breaks on an irregular surface rather than along cleavage planes N. Lindsley-Griffin, 1998 Types of fracture: Smooth Rough Splintery Conchoidal

8. © Houghton Mifflin 1998; Lindsley 2000 Hardness Mohs hardness scale: 1 = softest mineral; 10 = hardest Diamond 10 Corundum9 Topaz8 Quartz7 Feldspar6 Steel file(6.5) Apatite5Glass(5.5- 6) Fluorite4 Calcite3Copper penny(3.0) Gypsum2Fingernail(2.5) Talc1 Hardness -- the resistance to being scratched Mohs scale measures relative hardness, the ability of one mineral to scratch another

9. The 10 minerals of Mohs relative hardness scale 1 Talc2 Gypsum 3 Calcite 4 Fluorite 5 Apatite 6 Feldspar 7 Quartz 8 Topaz 9 Corundum 10 Diamond N. Lindsley-Griffin, 1999

10. © Houghton Mifflin; N. Lindsley-Griffin, 1998. Luster Luster - the appearance of a mineral in reflected light Types of luster: Metallic Nonmetallic Pearly Vitreous Resinous Silky Dull Earthy Metallic luster of pyrite Earthy luster of limonite

11. Metallic Luster is characteristic of ore minerals and others that contain metal cations. N. Lindsley-Griffin, 1998

12. Resinous luster in sphalerite Pearly luster in talc N. Lindsley-Griffin, 1999