Minerals and Mineral
Identification
FIRST LESSON IN GEOLOGY
What is a Mineral?
A. Mineral: A naturally occurring,
inorganic solid substance that has a
definite chemical composition.
1. This means that it is NOT manmade,
that it DOES NOT come from something
living or once living, and what it is made
up of is known.
What Gives Minerals Their Physical Properties?
2. The internal arrangement of atoms gives
minerals their different physical properties
a. These properties include things like:
hardness, breakage pattern and streak
b. An example of minerals that have the same
composition but different physical
properties is: graphite and diamond
c. Graphite = pencil lead
d. Diamond= hardest mineral, valuable!
B. Properties Used to Identify Minerals
1. Color
a. It is difficult to tell what a
mineral is based on color
because minerals can be
multiple colors and many
minerals are the same color.
2. Streak
themore
powder
reliable
formthan
of a color
mineral
3. 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
4. Cleavage
-mineral breaks in a predictable pattern
because of its arrangement of atoms
-At least one distinct flat side when broken
5. Fracture
-the mineral breaks randomly
-Irregular sides
6. Hardness
1. resistance to being scratched- a softer
material cannot scratch a 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.
Do not write:
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