Presentation on theme: "Minerals 1.Naturally occurring 2.Inorganic 3.Solid - crystalline (orderly) structure. -- Can be elements or compounds."— Presentation transcript:
Minerals 1.Naturally occurring 2.Inorganic 3.Solid - crystalline (orderly) structure. -- Can be elements or compounds.
Minerals Over 4,500 minerals identified. About 100 are common. Only about 10 elements make up most minerals. Silicon and oxygen are majority.
Identification Luster: Is it metallic (shiny) or non-metallic (dull)? Hardness (Mohs Scale): Resistance to scratching. *Based on internal arrangement of atoms. *Use glass plate to test for hardness
Hardness of Common Objects Fingernail =2.5 Penny =3.5 Glass = 5.5 Streak Plate = 7.0
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.
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.
Last ID Special Properties: 1.Magnetism 2.Luminescence - radiation 3.Piezoelectricity - electricity when pressure is applied (quartz). 4.Double Refraction - Calcite
Crystal Structure Most abundant elements in Earths 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.