Presentation on theme: "Minerals Naturally occurring 2. Inorganic"— Presentation transcript:
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 = 2.5Penny = 3.5Glass =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 IDStreak: 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 StructureMost 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.