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Minerals: the building blocks of rocks. Definition of a Mineral: naturally occurring inorganic solid characteristic crystalline structure definite chemical composition. . How do we identify minerals?. Physical properties:ColorLusterHardnessCrystal shapeCleavage Specific gravityOther.
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1. Chapter 3: Matter and Minerals (part II)
2. Minerals: the building blocks of rocks Definition of a Mineral:
naturally occurring
inorganic
solid
characteristic crystalline structure
definite chemical composition
3. How do we identify minerals? Physical properties:
Color
Luster
Hardness
Crystal shape
Cleavage
Specific gravity
Other
4. Physical Properties of Minerals Color:
Most obvious, but often misleading
Different colors may result from impurities
5. Physical Properties of Minerals Color:
Streak – color of a mineral in powdered form
(used for metallic minerals)
6. Physical Properties of Minerals Luster:
How a mineral surface reflects light
Two major types:
Metallic luster
Non-metallic luster
7. Physical Properties of Minerals Hardness:
How easy it is to scratch a mineral
Mohs Scale of Hardness
relative scale
consists of 10 minerals, ranked 1 (softest) to 10 (hardest)
8. Mohs Scale of Hardness
9. Physical Properties of Minerals Crystal shape (or form):
external expression of a mineral’s internal atomic structure
planar surfaces are called crystal faces
angles between crystal faces are constant for any particular mineral
10. Physical Properties of Minerals Cleavage vs. Fracture:
The way a mineral breaks
11. Physical Properties of Minerals Cleavage is described by:
Number of planes
Angles between adjacent planes
12. Physical Properties of Minerals Cleavage (1 direction):
13. Physical Properties of Minerals Cleavage (2 directions):
14. Physical Properties of Minerals Cleavage (3 directions):
15. Physical Properties of Minerals Cleavage (4 directions):
16. Physical Properties of Minerals Fracture:
minerals that do not exhibit cleavage are said to fracture
17. Physical Properties of Minerals Specific gravity:
weight of a mineral divided by weight of an equal volume of water
metallic minerals tend to have higher specific gravity than non-metallic minerals
18. Physical Properties of Minerals Other properties:
19. Rock-forming minerals
~30 common minerals make up most rocks in Earth’s crust
Composed mainly of the 8 elements that make up over 98% of the crust Mineral Groups
20. Mineral Groups
21. Mineral Groups Silicates (most abundant)
Non-silicates (~8% of Earth’s crust):
22. Mineral Groups – Silicates Silicates
Tetrahedron
fundamental building block
4 oxygen ions surrounding a much smaller silicon ion
23. Mineral Groups – Silicates Joining Silicate Structures
How tetrahedra may be linked:
independent tetrahedra
single chains
double chains
sheets
3-D framework
24. Mineral Groups– Silicates –
25. Mineral Groups – Silicates
26. Mineral Groups – Silicates
27. Mineral Groups – Silicates
28. Mineral Groups – Silicates
29. Mineral Groups – Silicates
30. Mineral Groups – Silicates
31. Mineral Groups