What Does Rock Comprise Of?

A rock is a solid substance made up of inorganic solids called minerals. Each mineral has a distinct crystalline structure and a unique chemical composition of its own. There are three types of rocks, namely igneous, sedimentary and metamorphic rocks. Each of these types of rocks is formed after undergoing a different geological process. The three fundamental geological processes are the solidification of magma, the sedimentation of debris from rocks that have undergone weathering and metamorphism or change, which occurs over a period of time.

Igneous rocks are formed by the solidification of molten magma. This magma oozes out of the mantle of the Earth and falls onto the surface of the Earth. When the magma subsequently cools and solidifies on the Earth's surface, there is a formation of a group of rocks called extrusive or volcanic igneous rocks, and the rocks formed beneath the surface of the Earth after the magma has cooled and solidified are known as intrusive or plutonic igneous rocks.

Sedimentary rocks are formed when the debris of rocks or sediments get deposited at the surface of the Earth and are subsequently either buried, compressed or chemically modified. Metamorphic rocks are created by the chemical and physical modification of an existing rock when it comes into contact with intense heat and pressure.