Mineral Formation. Methods of Formation Crystals may form from magma cooling Cools slow = large...
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Transcript of Mineral Formation. Methods of Formation Crystals may form from magma cooling Cools slow = large...
Mineral Formation
Methods of Formation
Crystals may form from magma cooling Cools slow = large crystals Cools quickly = small crystals Confined space = small crystals Open space = large crystals
Crystals may form out of solution. As liquid evaporates, mineral is left behind Ex/ “Bad Koolaide”, sea salt on skin
Silicates
Structure of all silicates is a Tetrahedron
1 Silicon & 4 Oxygen arranged in a pyramid structure
96% of minerals are known as silicates.
Oxygen nearly 50% of the Earth’s crust. Silicon makes up over 27%
Carbonates & Oxides
Carbonates
Metal + carbonate CO3
Fizz in the presence of HCl acid
Ex/ marble, limestone, & calcite
Oxides
Metal + oxygen
Good sources of iron
Ex/ Magnetite & Hematite
Other Mineral Groups
Sulfides = sulfur + another element (Pyrite)
Sulfates = sulfate (SO4) + another element
Halides = Cl or F (fluorine) bonded with a calcium, sodium or potassium
Native elements = made of one element only (Gold, Silver, Sulfur, etc.)
Mineral Use Categories
Remember that minerals make up the entire crust Making up rocks On their own
Many are used for economic reasons
2 economic categories Ore minerals Gems
Ore Minerals
Ore: mineral found with in deposits that can be profitably mined
This means that the money earned from the ore itself outweighs the cost of extracting it
Most ores are found as compoundsWhile many precious metals are native
Ore Examples
Chalcopyrite: mined for Copper
Galena: mined for Lead
Sphalerite: mined for Zinc
Halite: mined for table salt
Gypsum: Sheet rock (dry wall) & plaster
Hematite: source of Iron
Bauxite: source of Aluminum
Gems
Gems are valuable for their beauty rather than their industrial uses Precious Semi-precious
The rarer the gem, the more valuableEmeralds & Rubies are actually more valuable than
diamonds
Trace elements can make an ordinary mineral more prized Ex/ Amethyst: form of quartz; trace elements make it purple
More on Gems
PreciousDiamonds
Emeralds
Rubies
Sapphires
Opals
Semi-preciousAmethystJasperAgateTiger EyeSometimes Turquoise Topaz Garnet