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 (CO 3 ) Calcite - Ca CO 3, Dolomite - CaMg (CO 3 ) 2 Main component of the rocks limestone & dolostone. 3) Oxides – usually metals + oxygen Hematite - Fe 2 O 3 (Iron Oxide or Rust), Corundum - Al 2 O 3 (Aluminum Oxide or Ruby). Excellent source of ore metals

Other Important Mineral Groups 4) Sulfides – based on sulfide ion (S 2- ) Pyrite - FeS 2 (“Fool’s Gold”) Excellent source of ore metals 5) Sulfates – based on sulfate ion (SO 4 ) - Gypsum - CaSO 4 (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!!