Download Minerals

Field Trip #1: Hocking Hills State Park
Saturday, October 2nd
MINERALS: The Building Blocks of Rocks
Definition of a Mineral
• A Mineral is a naturally occurring,
inorganic, solid, crystalline substance,
with definite physical and chemical
properties.
• Inorganic – not composed of Carbon – Hydrogen
molecules (usually part of living tissue)
• Crystalline – atoms have a structured
arrangement.
CRYSTAL SHAPES
How Do Crystals Form?
Remember Atomic Structure
ATOMS DO NOT WANT TO BE NEUTRAL
THEY WANT TO BE STABLE
 Stable Means Having Their Outer Shell Of
Electrons Full To Capacity
 This Can Happen By Losing Or Gaining
Electrons to Other Atoms
This Process causes Atoms to Join Together:
A Process Called Bonding
1) IONIC BONDING
2) COVALENT BONDING
OTHER BONDS
3) Metallic – Electrons act as a mobile cloud
that moves from atom to atom. Accounts for
excellent electrical conductivity of metals
Example: Copper
4) van der Waals – Very weak Bond due to
slight polarity of charge on atoms
MINERAL PROPERTIES: HARDNESS
MINERAL PROPERTIES: CLEAVAGE
Breakage along planes of crystal weakness
MINERAL PROPERTIES: Other Properties
Color
Streak – color of powdered mineral
Luster – the way light reflects of a mineral
Specific Gravity –
Weight of Mineral
Weight of same volume of water
Fracture – breakage through crystal
Reactivity – Reacts with Acid?
MAJOR MINERAL GROUPS
What are the most common minerals in the Crust?
1) What are the most common elements?
1)
SILICATES – Made From Silicon + Oxygen
> 91% of all crustal minerals
The Silicon – Oxygen Tetrahedron
The Silicon – Oxygen Tetrahedron can bond together in
many different ways producing many different minerals
Other Important Mineral Groups
2) Carbonates – based on Carbonate ion (CO3)
Calcite - Ca CO3, Dolomite - CaMg (CO3)2
Main component of the rocks limestone &
dolostone.
3) Oxides – usually metals + oxygen
Hematite - Fe2O3 (Iron Oxide or Rust),
Corundum - Al2O3 (Aluminum Oxide or Ruby).
Excellent source of ore metals
Other Important Mineral Groups
4) Sulfides – based on sulfide ion (S2-)
Pyrite - FeS2 (“Fool’s Gold”)
Excellent source of ore metals
5) Sulfates – based on sulfate ion (SO4)Gypsum - CaSO4 (Drywall)
Used in the construction industry
So, why study minerals?
1) Building Blocks of Rocks – what the Earth is made of.
2) Important Economically – Industry & Agriculture.
3) Can be incredibly beautiful!!