The 8 most common elements in the Earth’s crust are oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium.
They compose 98.5% of the total crust. A mineral occurs naturally, is a solid, inorganic, has a chemical composition, and a crystalline structure. Native minerals are single elements. Compounds are two or more. There are more compounds than native.
You can identify minerals by their color, streak, luster, hardness, cleavage, and fracture. Minerals form by magma erupting and forming lava, which then cools. They can also form by the evaporation of water containing dissolved ions. Silicates are the most common group of minerals found in the Earth’s crust. The structure of minerals is orderly.
They form crystalline structures. A crystal 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 and have a fine grain. The scheme for igneous rock identification is based on texture, color, composition, and density.
Sedimentary rocks are the second step in the rock cycle. They are composed of bits and pieces of rock that have been eroded by rain, water, and other forces. These sediments compress and cement on top of each other, forming layers. When the water evaporates, the sediments are left behind and form a new rock.
This rock is either clastic or organic. Clastic rocks are formed from igneous rock, while organic rocks are formed from living remains. The third type of sedimentary rock is chemical, which is formed by the evaporation of water and the precipitation of sediments that form a new rock. Metamorphic rock is formed through the recrystallization of rocks under extreme heat and pressure. Regional metamorphism occurs over large areas where mountain building has taken place, while contact metamorphism occurs when molten magma comes into contact with surrounding rocks. Category: Science.