Rocks
By: Katelynn Acevedo
What is a rock?
A rock is composed of minerals. They are classified by how they were formed. There are three types of rocks, igneous, sedimentary, and metamorphic.
Igneous Rocks
Igneous Rocks are formed by melting and solidification. Igneous rocks are formed inside of the volcano. The main types of igneous rocks are intrusive and extrusive. Intrusive Igneous Rocks are rocks that crystallize slowly inside the earth's crust. Extrusive Igneous rocks are rocks that crystallize quickly and these are how both are formed.
Sedimentary Rocks
Sedimentary Rocks are formed by the compaction and cementing of sediments. They are formed at or near the Earth's surface. The types of Sedimentary Rocks are Clastic (fragmental) sedimentary rocks, Bioclastic (organic) sedimentary rocks, and Crystalline Sedimentary Rocks. Clastic sedimentary rocks are formed by different sized particles being cemented together. Bioclastic sedimentary rocks are formed by the accumulation of plant and animal remains. Crystalline sedimentary rocks are formed when deposited chemicals in sea water precipitate and fall to the ocean bottom and evaporates.
Metamorphic Rocks
Metamorphic Rocks are formed by heat and pressure without melting. The two types of Metamorphic Rocks are Foliated and Non Foliated. Foliated Metamorphic Rocks are formed under high pressures that are unequal. Non Foliated metamorphic rocks are formed when temperatures are high but pressures are low.
Diorite
Diorite is an Igneous Rock so it is formed within the volcano. Its texture is non vesicular and coarse. It is an intrusive igneous rock. Diorite is in between light and dark. Its density is between low and high and its composition is between felsic and mafic. It is made up of 30% of amphibole, 10% biotite and 55% of potassium feldspar.
Rock Salt
Rock Salt is a Sedimentary Rock so it is formed at or near the earth's surface. It is a chemically formed sedimentary rock. Its texture is Crystalline and its grain size is fine to coarse crystals. Its composition is Halite. The crystals from chemicals precipitates and evaporites.
Marble
Marble is a nonfoliated metamorphic rock. Its texture is nonfoliated and its grain size is fine to coarse. Its composition is Calcite and/or dolomite. Marbles type of metamorphism is regional or contact. It is metamorphism of limestone or dolostone.
Rock Cycle
The Rock Cycle is a model showing how rocks and sediments change over time.