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3 Types Of Rocks Essay

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Comparing rocks
Minerals make up rocks. Rocks are formed in many environments upon and within the Earth's crust. There are three types of rock, each formed in a different `way. Igneous rock , formed by the cooling of magma (molten rock) inside the Earth or on the surface. Sedimentary rocks, formed from the products of weathering by cementation or precipitation on the Earth’s surface. Metamorphic rocks
, formed by temperatur e and pressure changes inside the Earth. All three types of rock make up the Earth’s lithosphere, the outermost layer. The lithosphere averages about 100 kilometers in thickness.Sedimentary rocks form at the Earth’s surface in two main ways. Clastic material (pieces of other rocks or fragments of skeletons) may become cemented together and chemical precipitation and evaporation can form sedimentary rocks. All igneous rocks began as magma (molten rock) which cooled and crystallized into minerals. Geologists classify igneous rocks based on both their crystal size and composition. Igneous rocks may look different because they may have cooled at different rates and the "mother" magma (original melted rock) was of a different composition. Variations in these two factors have created many igneous rocks. When the magma cools at different the coal cools.
Metamorphic Rocks
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The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.Metamorphic rocks can be formed from any other type of rock - sedimentary or igneous. Remember these two examples of common metamorphic rocks and where they come from: slate is formed from shale.main ways. Clastic material (pieces of other rocks or fragments of skeletons) may become cemented together and chemical precipitation and evaporation can form sedimentary
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