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Minerals
Key Concept #1
What is a mineral?
A mineral is a
substance which has a
naturally occurring inorganic
definite chemical composition
What would be the opposite of this?
man-made organic random composition
ESRT Mineral Chart Click Here
Key Concept #2
The reason why minerals have different physical properties is due to
their internal arrangement of atoms
Key Concept #2
An example of two minerals which have the same chemical composition but different physical properties is
Click Here
Key Concept #3
The Main Physical Properties Used to Identify Minerals
A. Color
1. a poor indicator
a. minerals can be multiple colors
b. many minerals are the same color
Key Concept #3
The Main Physical Properties Used to Identify Minerals
B. Streak
the powder form of a mineralmore reliable than color
Key Concept #3
The Main Physical Properties Used to Identify Minerals
C. Luster
how light reflects off a mineral
a. metallic b. non-metallic-looks like a metal
-Leaves a dark (black, grey, green or brown)
streak on a white streak plate
-looks earthy, waxy, greasy or brilliant-leaves white or no
streak on a black streak plate
Key Concept #3
D. Cleavage
The Main Physical Properties Used to Identify Minerals
-mineral breaks in a predictable patternbecause of its arrangement of atoms
-At least one distinct flat side when broken
Key Concept #3
E. Fracture
The Main Physical Properties Used to Identify Minerals
-the mineral breaks randomly-Irregular sides
Key Concept #3
F. Hardness
The Main Physical Properties Used to Identify Minerals
1. resistance to being scratched- something softer than a material cannot scratch the
harder material
2. It is NOT the same as breaking!
For example: You can break glass easily with steel.However, steel will not scratch glass.
Key Concept #3
Hardness
The Main Physical Properties Used to Identify Minerals
MOH’S SCALE OF HARDNESS
Hardness
Mineral Hardness
Mineral
1 (softest) 6
2 7
3 8
4 9
5 10 (hardest)
TALC
GYPSUMCALCITE
FLUORITE
APATITE
ORTHOCLASE
QUARTZTOPAZ
CORUNDUMDIAMOND
Key Concept #4
Minerals have a definite chemical composition.
The two elements by mass that make up the greatestpercentage of the Earth’s crust are
siliconoxygen
Key Concept #4
Minerals have a definite chemical composition.
These two elements combine to form compounds called
silicates (SiO4)
Key Concept #4
Minerals have a definite chemical composition.
They combine in a specific structure called a:
silicon-oxygen tetrahedra
REVIEW- WHAT IS A MINERAL?A mineral is naturally
occurring, inorganic, and crystalline solid having a definite chemical composition
Each mineral has its own distinctive crystal structure that can lead to a very accurate ID
All minerals are solids that are composed of one or more chemical elements
All minerals are rocks, but not all rocks are minerals nor are they all composed of minerals- the main reason: rocks can be organic like coal
Minerals form as the result of inorganic crystallization or by the re-crystallization of atoms in various rock-forming environments
Minerals can be identified by color, streak, luster, hardness, density, cleavage, crystal structure and other characteristics (ex. magnetism, response to hydrochloric acid, etc)
