 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  • 2 nd 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  Hardness  Luster  Density  Cleavage  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 color  Streak

 How light reflects  2 main types • •  Metallic Looks like it is made of metal  Non-Metallic Looks more glassy

CLEAVAGE   Break along flat surfaces.

• Tells us how the atoms are bonded. • The mineral is weaker in the direction it breaks.

Mica FRACTURE   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 and pyrite  The 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.

 Useful in identifying minerals.

FLOURESCENCE  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.