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Minerals . 5 characteristics. 1. Naturally occurring 2. Solid 3 . Orderly crystalline structure 4. Definite chemical composition 5. Generally inorganic. Mineral Formation - Four Major Processes. 1. Crystallization from magma
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5 characteristics 1. Naturally occurring 2. Solid 3. Orderly crystalline structure 4. Definite chemical composition 5. Generally inorganic
Mineral Formation - Four Major Processes 1.Crystallization from magma • first minerals to crystallize are those rich in Iron, Calciumand Magnesium • as minerals form the composition of magma changes and minerals rich in Sodium, Potassium, and aluminum then form
2. Precipitation • occurs when water evaporates • Changes in water temp. also causes minerals to be left behind, called precipitates • 2 example s are Limestone and Halite
3. Pressure and Temperature • formed when existing minerals are subject to Pressure and Temperature • Pressure causes atoms to rearrange in a more compact form • Temperature causes some minerals to become unstable the new mineral are now stable
4. Hydrothermal solutions • a very hot solution of water and dissolved substances • hydrothermal solution have temperature between 100 and 300 degrees Celsius • a chemical reaction causes new minerals to form
Mineral Groups • 6 major groups of minerals based on chemical composition
Silicates – most common • formed from Silicon and Oxygen • 1 Silicon atom and 4 oxygen atoms form the shape of a Tetrahedron. • This is the framework for all silicates
Silicon – Oxygen tetrahedron can be joined in many configurations • Single - tetrahedral (ex: olivine) • Single chain (ex: augite) • Double chain (ex: Hornblende) • Sheets (ex: micas) • 3D framework (ex: quartz and feldspar) • Formation occurs when magma cools • Place and chemical composition determine structure
Carbonates – 2nd most common • contain the elements Carbon, Oxygen and 1 other metallic element • most common carbonate is Calcite • examples of carbonates are Dolomite
Oxides • minerals that contain Oxygen and 1 other element • examples of oxides are Rutile, Corundum, Hematite • various ways of forming: Temperature, Pressure, exposure to water, moisture in the air
Sulfates and Sulfides • contain the element Sulfur • examples of sulfates and sulfides are anhydrite, gypsum • various ways of forming: evaporating mineral rich water (precip), and hydrothermal solutions
Halides • contain a halogen • Halogens are in group 17 of the Periodic Table • examples of halogen are halite, fluorite
Native Elements • a. minerals that contain only 1 element • b. examples of native elements are gold, silver, graphite