1. Identifying Minerals
Properties: Color, Luster, Streak, Density, Hardness, Cleavage, Fracture, and Special Properties

2. Color The same mineral can come in a variety of colors
Ex. quartz
Impurities & other factors can change mineral appearance
Color is not the best way to identify minerals

3. Luster Describes how a surface reflects light
Ex. shiny/dull
Metallic- minerals containing metals are often shiny

4. Luster Examples of Nonmetallic Nonmetallic- not as shiny
Vitreous- glassy, brilliant
Silky-fibrous
Resinous-plastic
Waxy- greasy, oily
Pearly- creamy
Earthy- rough, dull
Nonmetallic- not as shiny

5. Streak Color of mineral in powder form
Observed by rubbing a mineral against a piece of unglazed porcelain called a streak plate
Streak doesn’t vary like color & is often different than a mineral’s color
More reliable than color

6. Cleavage and Fracture

7. Cleavage and Fracture- ways the mineral breaks apart, determined by arrangement of atoms.

8. Hardness Minerals resistance to being scratched
Mohs’ Hardness Scale: Ranks minerals from softest to hardest
Talc- softest known mineral
Diamond- hardest known mineral

9. Hardness

10. Mohs Hardness Scale Talc 1 Softest known mineral
Gypsum 2 fingernail can scratch it
Calcite 3 scratched by copper penny
Fluorite 4 easily scratched by steel knife
Apatite 5 can be scratched by steel knife
Orthoclase 6 can scratch window glass
Quartz 7 can scratch steel
Topaz 8 can scratch quartz
Corundum 9 can scratch topaz
Diamond 10 hardest known mineral

11. Density
mass (how heavy it is) per unit volume (how much space it takes up)
D= M/V
Density remains same regardless of sample size
Mass determined using balance
Volume determined using water
displacement method.
Ex: gold is heavier than pyrite
(fools gold)