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A
substance that:
• Forms in nature
• Is a solid
• Has a definite
chemical make-up
• Has a crystal structure
 All
minerals form in nature.
• Most involve non-living things
• Some can also be produced by organisms that
grow bones or shells
 Have
a definite volume and a rigid
shape.
 Water
is not a mineral, but ice is. Explain.
 Element-
substance that contains one
type of atom.
 All minerals are made of elements or
compounds.
• Compounds are groups of elements
• Minerals made of compounds are made of the
same couple of elements in certain proportions.
 Crystal-
A solid in which atoms are
arranged in an orderly, repeating, 3
dimensional pattern.
 Graphite and Diamonds are made of the
same thing.
• Different arrangements create different
substances.
 Perfect
crystals are rare.
 Silicates
• Silicon and Oxygen
• 90% of the rocks on the earth’s crust
 Carbonates
• Carbon and Oxygen
• 2nd most common mineral group
 Oxides
• Contains minerals from which most metals are
refined
 We
identify minerals by testing them
against properties that are known.
 Each
mineral has certain properties.
 Color
 Density
 Hardness
 Cleavage
 Luster
 Fracture
 Some
minerals can be any color.
 Tiny
bits of elements that is not part of its
normal makeup.
 Near
the earth’s surface.
 Defects
 Outer
 Streak
color
 How
2
light reflects
main types
• Metallic
 Looks like it is made of metal
• Non-Metallic
 Looks more glassy
CLEAVAGE

Break along flat surfaces.
FRACTURE

• Tells us how the atoms are
bonded.
• The mineral is weaker in
the direction it breaks.

Mica

Tendency to break into
irregular pieces.
The bonds that join atoms
are fairly strong in all
directions
 The
amount of mass in a given volume.
 Gold
 The
and pyrite
mass of gold is almost 4x pyrite
 Resistance
to being scratched.
 Determined
by the atoms’ bond.
• Stronger bonds make harder minerals
 Can
be scratched by minerals with equal
or more hardness.
REACTIONS



Example: Calcite
React with acid.
The acid will bubble and
CO2 will form.
FLOURESCENCE




Useful in identifying
minerals.
Example: Flourite
Glow when exposed to
ultra-violet light.
Limited value in identifying
minerals.
MAGNETIC


Example: Magnetite
Magnets are commonly
used to separate magnetic
and non-magnetic minerals
RADIOACTIVITY




Contain unstable elements.
Change into other elements
over time.
When they change, they
release energy.
That is what is measured to
determine radioactivity.