Earth Science Rocks Essay Example For Students

Earth Science Rocks Essay The 8 most common elements in the earths crust are Oxygen, Silicon, Aluminum, Iron, Calcium, Sodium, Potassium, ; Magnesium. They compose 98.5% of the total crust. A mineral occurs naturally, is a soli, inorganic, has chemical composition and a crystalline structure. Native minerals are single elements. Compounds are 2 or more. There are more compound than native. You can identify minerals by color, streak, luster, hardness, cleavage, and fracture. Minerals form by magma erupting and forming lava then cooling. They can also form by evaporation of water containing dissolved ions. Silicates are the most common group of minerals found in the earths crust. The structure of minerals are orderly. They form crystalline. A crystalline has flat faces and smooth surfaces. Igneous rocks are formed from magma. If they are intrusive (plutonic), they have large crystals and cooled slowly. If they are extrusive, they cool quickly, have fined grain. The structure of minerals are orderly. They form crystalline. A crystalline has flat faces and smooth surfaces. Igneous rocks are formed from magma. If they are intrusive (plutonic), they have large crystals and cooled slowly. If they are extrusive, they cool quickly, have fined grain. The scheme for igneous rock identification is based on texture, color, composition, and density. Sedimentary rocks are the 2nd step in the rock cycle. They are composed of bits and pieces of rock that have been watered by rain, water, and other things. They compress and cement on top of each other forming layers. When the water evaporates, the sediments are left behind and forms a new rock. This rock is either clastic (formed from igneous rock) or organic (formed from living remains). The other type of sedimentary rock is chemical which is formed by the evaporation of water and the precipitation on sediments form a new rock. Metomorphic rock is the recrystalization (change w/o melting) of rocks under extreem heat and pressure. Regional metamorphism occurs over large arieas where mountain building has taken place. Comtact metamorphism occurs when molten magma comes into contace w/ sourounding rocks. .