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Types of Minerals. Chapter 4 Section 2. Mineral Groups. Silicates Minerals that contain silicon and oxygen Make up 96% of minerals in Earth’s crust Tetrahedron Building block of silicates Geometric solid having four sides that are equilateral triangles Resemble a pyramid
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Types of Minerals Chapter 4 Section 2
Mineral Groups Silicates • Minerals that contain silicon and oxygen • Make up 96% of minerals in Earth’s crust • Tetrahedron • Building block of silicates • Geometric solid having four sides that are equilateral triangles • Resemble a pyramid • Silica tetrahedra has one silica atom and 4 oxygen atoms • Silica tetrahedron can form in a variety of combinations • Accounts for the large diversity of silicate minerals.
Silicates • Individual tetrahedra are strongly bonded • Sheets • Chains • Complex three-dimensional structures • Bonds determine the • fracture or cleavage properties • Weak ionic bonds break along sheets- mica
Carbonates • Minerals composed of one or more metallic elements and the carbonate ion CO32-. • Examples: • Calcite • Dolomite • Rhodochrosite • Found mostly in rocks such as limestone and marble • Have distinctive colorations
Carbonates Calcite Dolomite
Oxides • Compounds of oxygen and metals • Hematite and Magnetite common iron oxides • Uranitite- source of uranium Hematite Magnetite Uranitite
Other Groups • Sulfides • Pyrite (fool’s gold) • Sulfur and one or more elements • Sulfates • Anhydrite • Sulfate ion and other elements • Halides • Halite • Chloride and fluoride along with calcium • Native elements • Silver, or copper • Made of one element only
Economic Minerals • Ore • A mineral is an ore if it has value. • As soon as the value is gone, it is no longer an ore • Gems • Valuable minerals that are prized for their rarity and beauty. • Very hard and scratch resistant • Emeralds, rubies, diamonds • Polished and use for jewelry Platinum ore