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2 - MINERALS Building Blocks of Rocks. Matter & Atomic Structure Bonding Minerals Physical properties of minerals Major rock-forming mineral families Silicates - rock-forming SUPER STARS. Structure of an Atom. Protons +/1 Neutrons 0/1 Electrons -/0.
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2 - MINERALSBuilding Blocks of Rocks • Matter & Atomic Structure • Bonding • Minerals • Physical properties of minerals • Major rock-forming mineral families • Silicates - rock-forming SUPER STARS
Structure of an Atom Protons +/1 Neutrons 0/1 Electrons -/0
BONDING - 4 kinds • IONIC - electrical charge • COVALENT - sharing • METALLIC - inner shell covalent bond • INTERMOLECULAR - Van der Waal’s
MINERALS - Rock Builders • NATURALLY FORMED • INORGANIC • CRYSTALLINE & SOLID • DIAGNOSTIC CHEMICAL COMPOSITION
CRYSTALLINE SOLID Galena (PbS)
Atomic Structure of Galena Sulfur Lead DIAGNOSTIC CHEMICAL COMPOSITION
Ionic Radii & charge of some geologically important ions allows “ionicsubstitution” or SOLID SOLUTION
WHAT FACTORS DETERMINE WHAT MINERAL WILLFORM? • WHAT ELEMENTS ARE AVAILABLE • ABUNDANCE OF EACH ELEMENT • SIZE & CHARGE OF EACH ELEMENT • ENVIRONMENT - SPACE, PRESSURE, TEMPERATURE
Crystal Habit Cleavage & Fracture * Striations Hardness Specific Gravity Color Streak Luster Acid Test Identify Minerals by Their Physical Properties
Crystal Form - Constancy of Interfacial Angles Constancy of Interfacial and Angles in Quartz
MOH’S HARDNESS SCALE Examples Brian Skinner
Ruby The Different Colors of Corundum Sapphire
GALENA (Pb S) - Identified by:crystal habit luster specific gravity hardness
Average Composition of the Continental Crust O O Si Weight Percent Volume Percent
COMMON ROCK-FORMINGMINERAL FAMILIES • NATIVE ELEMENTS - GOLD, COPPER • HALIDES - PRECIPITATES • OXIDES - 1 METAL + OXYGEN • SULFIDES - 1 METAL + SULFUR • SULFATES - (SO4)2- • CARBONATES - (CO3)2- • SILICATES - SUPER STARS!!!
About Silicates • There are 2 families of silicates: • FERROMAGNESIAN SILICATES - Fe/Mg -> MAFIC MINERALS • NONFERROMAGNESIAN or ALUMINO- SILICATES -> FELSIC MINERALS
Olivine: (Mg,Fe)2SiO4 formed from single silica tetrahedra
Pyroxene Cleavage in the Chain Silicates Amphibole
Clay: a sheet silicate SHEET SILICATES
Polished Section ~1 cm
Thin section under ordinary light Magnetite Feldspar Mica Quartz