1. Mineral Formation

2. 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 solutionCrystals may form out of solution. As liquid evaporates, mineral is left behind Ex/ “Bad Koolaide”, sea salt on skin

4. 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%

5. Carbonates & Oxides Carbonates Metal + carbonate CO 3 Fizz in the presence of HCl acid Ex/ marble, limestone, & calcite Oxides Metal + oxygen Good sources of iron Ex/ Magnetite & Hematite

6. Other Mineral Groups Sulfides = sulfur + another element (Pyrite) Sulfates = sulfate (SO 4 ) + 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.)

7. 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

8. 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 compounds While many precious metals are native

9. 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

10. Gems Gems are valuable for their beauty rather than their industrial uses Precious Semi-precious The rarer the gem, the more valuable Emeralds & 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

11. More on Gems Precious Diamonds Emeralds Rubies Sapphires Opals Semi-precious Amethyst Jasper Agate Tiger Eye Sometimes Turquoise Topaz Garnet