1. Minerals Naturally occurring 2. Inorganic
3. Solid - crystalline (orderly) structure.
-- Can be elements or compounds.

2. Minerals Over 4,500 minerals identified. About 100 are common.
Only about 10 elements make up most minerals. Silicon and oxygen are majority.

3. Identification Luster: Is it metallic (shiny) or non-metallic (dull)?
Hardness (Moh’s Scale): Resistance to scratching.
*Based on internal arrangement of atoms.
*Use glass plate to test for hardness

4. Hardness of Common Objects
Fingernail = 2.5
Penny = 3.5
Glass =
Streak Plate = 7.0

5. ID Continued Cleavage / Fracture: How the mineral breaks.
Cleavage = mineral always breaks with a flat side.
Fracture = no smooth break; but some are distinctive. Ex. Conchoidal, fibrous, uneven.

6. More ID
Streak: color left after rubbing mineral on streak plate (usually porcelain).
Chemical Composition: in the laboratory.
Color: least reliable. WHY?
Minerals may occur in many different colors.

7. Last ID Special Properties: Magnetism Luminescence - radiation
Piezoelectricity - electricity when pressure is applied (quartz).
Double Refraction - Calcite

8. Crystal Structure
Most abundant elements in Earth’s crust = silicon and oxygen.
Silicon and oxygen form tight bond =
Tetrahedron (4 O Si)
Silicon can form with other elements to form rings, sheets, and frameworks.