1. Minerals

2. 4 requirements to be considered a mineral:
Naturally Occurring (not manmade)

3. 4 requirements to be considered a mineral:
Inorganic – not from living things
Arsenic minerals

4. 4 requirements to be considered a mineral:
Unique chemical composition (chemical formula)
Calcite

5. 4 requirements to be considered a mineral:
Definite structural pattern (crystalline)
Quartz

6. Relationship to Rocks Are minerals rocks? Yes
Are all rocks minerals? Not always
Why? Not all rocks fit the criteria of a mineral

7. Mineral Formation Precipitation: minerals settle out of solution
Crystallization: structured organization of atoms
Crystal size: depends on amount of time to grow

8. Physical Properties: Color – this is the LEAST RELIABLE
One mineral can come in many colors
Many minerals can be the same color
Quartz

9. Physical Properties:
Streak – the color of the mineral in powdered form
May be different than its color
More reliable
Pyrite

10. Physical Properties: Luster – how it shines or reflects light
Metallic (shiny) vs. nonmetallic (dull, glossy)
Metallic Luster Nonmetallic Luster

11. Physical Properties: Hardness – resistance to being scratched
Moh’s hardness scale
Ranges from 1 (soft) to 10 (hard)

12. Hardness Each number is a different mineral
Ex: 1= Talc, 10=Diamond, 7= Quartz

13. Hardness
The hardness of tools used to identify minerals can also be on the scale
Ex: Fingernail = 2.5
Penny = 3.5
Glass = 5.5
Steel nail = 6.5

14. Physical Properties:
Cleavage – tendency of a mineral to split along planes of weakness
Up to 3 planes

15. Physical Properties:
Fracture – uneven breaks (no cleavage)

16. Other Possibly Useful Properties:
Magnetic

17. Other Possibly Useful Properties:
Taste (not recommended)
Ex: Halite

18. Other Possibly Useful Properties:
Acid test – some minerals bubble in hydrochloric acid
Ex: Calcite

19. Other Possibly Useful Properties:
Double Refraction – can see two images through the mineral
Ex: Calcite

20. Other Possibly Useful Properties:
Fluorescence: glow under UV light

21. ***IMPORTANT: The physical properties of a mineral are due to the internal arrangement of its atoms!***