Download Minerals

Minerals
Unit 3 Notes
What is a mineral?
• A mineral must be all of the
following:
• Naturally occurring
• Inorganic solid (not living)
• Definite structure
• Definite composition (what it’s
made of)
What is a crystal?
• A crystal is a solid in
which the atoms are
arranged in repeating
patterns
Crystal Structure
Here are the six crystal systems
that all minerals belong to:
•Cubic – sylvite, halite
•Hexagonal – emerald, graphite
•Tetragonal – wulfenite, zircon
•Orthorhombic – topaz, sulfur
•Monoclinic – gypsum, mica
•Triclinic – kyanite, turquoise
Elements in Earth’s Crust
Oxygen
Silicon
Aluminum
Iron
Calcium
Sodium
Potassium
Magnesium
Other
Name
Symbol
% By Mass
Oxygen
O
46.6%
Silicon
Si
27.7%
Aluminum
Al
8.1%
Iron
Fe
5.0%
Calcium
Ca
3.6%
Sodium
Na
2.8%
Potassium
K
2.6%
Magnesium Mg
2.1%
Others
1.5%
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Mineral Composition
• Silicates (Si & O)
• Carbonates (C & O)
Silicates
The silica
tetrahedron consists
of four oxygen
atoms packed closely
around a single
silicon atom. Named
for its shape (like a
3D pyramid).
How do minerals form?
• 3 Ways:
–Cooling of molten rock (lava
or magma)
–Evaporation of liquid
–Saturated solutions
Mineral Crystal Size
• Small Crystals – indicates slow
cooling of molten rock
• Large Crystals – indicates fast
cooling of molten rock
Mineral Identification
• Color – color is the first
property you notice – this
st
is usually the 1 step in
identification, but the
least useful
Quartz and Fluorite
come in many
different colors
Mineral Identification
• Hardness – is a mineral’s
resistance to being
scratched
Moh’s Scale of Hardness
• Scale ranges from 1 to 10
• 1 is softest & 10 is hardest
Factoid
•What is the hardest
substance on Earth??
• A diamond is the hardest
substance
(10 on Moh’s scale)
Mohs Hardness Scale
10
Diamond
9
8
7
6
Corundum
Topaz
Quartz
Feldspar
5
4
3
Apatite
Fluorite
Calcite
2
1
Gypsum
Talc
Mineral Identification
• Streak – the color of the
powder left when a
mineral is rubbed against
a hard rough surface
(usually unglazed
porcelain)
Testing Mineral Specimens
Mineral Identification
• Luster – the way light
reflects from a minerals
surface
2 Types of Luster
• Metallic – shiny
• Nonmetallic – glassy,
brilliant, greasy, oily,
waxy, silky, or pearly
Metallic Luster
Pearly Luster
(Non-Metallic)
Vitreous Luster
(Non-Metallic)
Mineral Identification
• Cleavage – mineral breaks
along smooth surface
• Fracture – mineral breaks
unevenly (jagged)
Mineral Identification
• Specific Gravity –
comparing density of a
mineral to the density of
water
Mineral Identification
• Acid Test – some
minerals give off CO2
(carbon dioxide) when
acid is added.
If it’s a carbonate…
Mineral Usage
• Ore – mineral resource
mined for a profit
• Gem – mineral that is
beautiful, rare, and
valuable
Metals
• Metals are elements that
have metallic luster,
malleability, ductility, and
conductivity
Malleability
• the ability of a mineral to be
hammered without breaking
Ductility
• the ability to be pulled
and stretched without
breaking
Conductivity
• the ability to conduct
heat or electricity