2Different from minerals Can be organicClassified by:ColorTextureMineral compositionOrigin (how they were formed).Three main groups of rocks.
3Igneous Rocks Formed by cooled magma or lava. Found in volcanic regions2 types:Intrusive: Rocks that cool under Earth’s surface.Cool slowly.Grains of rock are biggerExtrusive: Rocks that cool on Earth’s surface.Cool quickly.Grains of rock are smaller, with more air spaces (pores)
5Sedimentary Rocks 5 step process creates sedimentary rocks Deposition: Sediments are laid down in a new location. Build up in layers.Weathering:Existing rock is broken down into sediments.Erosion:Sediments are carried away to a new locationCementation:Sediments are glued together by a chemical reaction.Compaction:Sediments are pressed together by the wieght of new sediment on top.
6Sedimentary Rocks cont. Usually seen in layers.Fossils are found only in sedimentary rocks.