1. Minerals

2. A. What is a mineral? Characteristics shared by all minerals:
1. Natural
occurs naturally
NOT manmade

3. What is a mineral? 1. Natural 2. Inorganic Is not alive
Was never alive

4. What is a mineral? 1. Natural 2. Inorganic 3. Crystalline
Atoms are arranged in an orderly pattern

5. What is a mineral? 1. Natural 2. Inorganic 3. Crystalline
4. Definite chemical composition
Chemical formula
SiO2 is Quartz

6. What is a mineral? 1. Natural 2. Inorganic 3. Crystalline
4. Definite chemical composition
5. Solid
Not a gas, not a liquid, not plasma, not a condensate

7. How will we remember this?
Natural
Inorganic
Crystalline
Definite chemical composition
Solid

8. Mineral Characteristics shared by all minerals: Now I Can Define mineralS!
Natural
Inorganic
Crystalline
Definite chemical composition
Solid

9. B. Physical Properties of Minerals
1. Color
First impression
Not very reliable because lots of minerals can occur in many different colors

10. Quartz
Amethyst
Clear
Citrine
Rose
Smoky

11. Fluorite
Clear
Blue
Green
Purple

12. Physical Properties of Minerals
1. Color
2. Streak
The TRUE color of a mineral
Color of a mineral’s powder

13. Streak
Minerals with a hardness greater than “7” usually don’t create a streak on the streak plate because they are harder than the Porcelain tile (unless the streak plate is specially made).

14. Physical Properties of Minerals
1. Color
2. Streak
3. Hardness
A mineral’s resistance to being scratched
Mohs Hardness Scale from 1-10
Hardness depends on how “tightly packed” the atoms are

15. Mohs Hardness Scale Hardest Softest Talc Gypsum Calcite Fluorite
Apatite
Potassium Feldspar
Quartz
Topaz
Corundum
Diamond
Hardest

16. Mohs Harness Scale: Talc Gypsum Calcite Fluorite Apatite
K Feldspar Quartz Topaz Corundum Diamond

17. Everyday Substances: Fingernail – 2.5 Penny – 3.5 Steel Nail – 4.5
Glass – 5.5
Emery Board – 6.5

19. Physical Properties of Minerals
1. Color
2. Streak
3. Hardness
4. Cleavage
Splits along definite planes

20. “Cleav” = to split
Cleaver

22. Physical Properties of Minerals
1. Color
2. Streak
3. Hardness
4. Cleavage
5. Fracture
Breaks irregularly, jagged edges

23. Fracture

24. Physical Properties of Minerals
1. Color
2. Streak
3. Hardness
4. Cleavage
5. Fracture
6. Luster
How light shines off a mineral
Metallic or Nonmetallic

25. Luster
Metallic
Nonmetallic

26. Physical Properties of Minerals: Used for Identification (I.D.)
Color
Streak
Hardness
Cleavage
Fracture
Luster

27. C. Special Properties 1. Magnetism Attracted to a magnet
Contains IRON, cobalt, or nickel

28. Special Properties 1. Magnetism 2. Double refraction
Looking through it, you see “double”
i.e. Calcite

29. Special Properties 1. Magnetism 2. Double refraction 3. Fluorescence
Glows under ultraviolet (UV) light

30. Fluorescence under ultraviolet, UV light

31. Special Properties 1. Magnetism 2. Double refraction 3. Fluorescence
4. Phosphorescence
Continues to glow even after the UV light has been removed

32. Special Properties 1. Magnetism 2. Double refraction 3. Fluorescence
4. Phosphorescence
5. Piezoelectric
Electricity is generated from pressure
Example: Quartz

33. Piezoelectric (Pressure=Electricity)

34. Special Properties 1. Magnetism 2. Double refraction 3. Fluorescence
4. Phosphorescence
5. Piezoelectric
6. Radioactivity
- certain minerals are radioactive
- these minerals can be dangerous

35. Special Properties Magnetism Double refraction Fluorescence
Phosphorescence
Piezoelectric
Radioactivity

36. D. Identification Tests
1. Hardness
2. Streak (True Color)
3. Acid Test
Use hydrochloric acid
Tests for carbonate (calcite)

37. Caves can form in rocks with calcite, like here in Harrisonburg!
Acid in groundwater dissolves the calcite