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Minerals. A Mineral is: Naturally occurring Synthetic gems are not considered minerals Inorganic Not formed from plant or animal processes (sugar is not a mineral) Solid Orderly crystal line structure
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A Mineral is: • Naturally occurring Synthetic gems are not considered minerals • Inorganic Not formed from plant or animal processes (sugar is not a mineral) • Solid • Orderly crystalline structure Opal is not a mineral because it does not have an orderly internal structure • Definite chemical and physical composition Salt = Sodium+Chloride (NaCl) Quartz = Silicon+Oxygen (SiO2) Opal
Crystal • A crystal is a solid in which the atoms are arranged in a repeating pattern.
Crystal Systems Cubic – (Halite - rock salt) Tetragonal – (Wulfenite: yellow Lead ore) Hexagonal – (Corundum: rubies, sapphires - hardness 9) Orthorhombic – (Topaz: gem - hardness 8) Monoclinic – (Gypsum: drywall - hardness 2) Triclinic – (Albite: a type of feldspar)
Minerals & Crystals may form in the following ways: • Cooling of magma • Fast Cooling produces small crystals (grains) • Slow Cooling produces large crystals (grains) Oil drums
2. Evaporation of minerals dissolved in liquid. Calcite in caves Bristol Dry Salt Lake Road salt left behind from evaporated salt water
Crystal Formation Cont. • Pressure and Temperature • Changes in temperature and pressure can cause minerals to recrystallize. Ex. talc & muscovite • Hydrothermal Solution • When hot solutions come in contact with existing minerals. Ex. some quartz & sulfur
Mineral composition Groups • A) Silicates - Largest group of rock-forming minerals. Contain silicon (Si) (Quartz, feldspar) - (SiO2)
B) Oxides : compounds made of oxygen (O) and metal or other ions FeFe2O4 Al2O3 Fe2O3
C) Carbonates: most common after silicates; basic unit carbonate ion (CO3)-2 combined with Ca, Mg, Fe, Cu, etc. Ca[CO3] CaMg[CO3]2
D) Sulfides: combinations of one or more metals with sulfur (S). FeS2 PbS
E) Native elements:about 20 of them, often occur in pure form (they are elements!!!) C - carbon Ag Au S C -carbon
Key Vocabulary terms: Native elements Crystal A Mineral is… Crystal Systems Sulfides Silicates Carbonates Oxides Fast Cooling produces… Slow Cooling produces…
Properties of Minerals • Color • Luster • Streak • Crystal Form • Hardness • Cleavage • Fracture • Density (Specific Gravity) • Special Properties
ANALCIME REALGAR CROCOITE TYUYAMUNITE MALACHITE TURQUOISE CAVANSITE AZURITE FLUORITE AMETHYST KAEMMERERITE BIXBYITE Color *Many minerals have different colors so this is a poor indicator for mineral id.
Luster: Metallic Non-Metallic • How light reflects off a mineral Dull Adamantine Pearly Waxy Earthy Virtreous
Streak • The color of a mineral in powder form Porcelain Tile
Crystal Form • Visible expression of a mineral’s internal arrangement of atoms.
Hardness Talc – Softest (1) • The measure of the resistance of a mineral to being scratched. Diamond – Hardest (10)
Cleavage • The tendency for a mineral to break along flat, even surfaces. Mica – cleavage in 1 direction
Fracture • The uneven breakage of a mineral Bone fracture is uneven Quartz Conchoidal Fracture (Obsidian)
Density (Specific Gravity)D=M/V • The ratio of an objects mass to it’s volume Same size bar of pyrite (fool’s gold) would be 8 lbs. Density = 5.02g/cc 31 lbs for 1 gold bar Density = 19.3g/cc
Special Properties peww Yummy… • Smell • Taste • Radiation • Florescent • Reacts with acid (HCL)
Mineral Notes Quiz #1-10 • Define: #1-5 1. Streak 2. Native Element 3. Fracture 4. Luster 5. Mineral
6. Jack bought a bunch of diamonds from a vendor. He puts the diamonds into a containers filled with quartz while he travels. When he unpacks his diamonds he finds they are all scratched. Did jack get ripped off? Why?
Fast cooling = _________ size crystals. • What is the name of the Hardness scale? • List some special properties of minerals. • The most abundant minerals on the Earth’s crust are from what mineral group?