Minerals
Key Concept #1
What is a mineral?
A mineral is a naturally occurring inorganic
substance which has a 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
themore
powder
reliable
formthan
of a color
mineral
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
The Main Physical Properties
Used to Identify Minerals
D. Cleavage
-mineral breaks in a predictable pattern
because of its arrangement of atoms
-At least one distinct flat side when broken
Key Concept #3
The Main Physical Properties
Used to Identify Minerals
E. Fracture
-the mineral breaks randomly
-Irregular sides
Key Concept #3
The Main Physical Properties
Used to Identify Minerals
F. Hardness
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
The Main Physical Properties
Used to Identify Minerals
Hardness
MOH’S SCALE OF HARDNESS
Hardness
Mineral
Hardness
Mineral
1 (softest)
TALC
6
ORTHOCLASE
2
GYPSUM
CALCITE
FLUORITE
7
QUARTZ
TOPAZ
CORUNDUM
APATITE
10 (hardest)
3
4
5
8
9
DIAMOND
Key Concept #4
Minerals have a definite chemical composition.
The two elements by mass that make up the greatest
percentage of the Earth’s crust are
oxygen
silicon
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)