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Unformatted text preview: What Rocks are Made of 11/02/2008 12:57:00 ← Rocks are made up of minerals ← ← How do minerals form? • Three ways… o Cooling From Melted rock (volcano) o Chemical Precipitation from a solution (the crystallized minerals left in a tea kettle after water has boiled away….or with salt stains on streets during the winter.) o Formation from solid state (diamond…graphite heated and squeezed to an extreme amount and then turns into a diamond). ← ← Some Key Minerals • 4000 minerals • 3 Key groups of minerals o Silicates (most abundant on earth….silicon and oxygen plus other elements) Made of two key atoms, silicon and oxygen. In a tetrahedron shape…. SiO 2 + other elements Make up 90% of the rocks in the continental crust “Light” versus “Dark” silicates in color and density (light is less dense, and usually brighter) Ex. Quartz is a Light silicate (SiO 2 ) Ex. Feldspar is a light silicate Ex. Pyroxene Dark silicate (Dark green)Ex....
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- Spring '07
- Geology, Granite, Basalt, magma cools, light silicate Ex