Granite is a light-coloured igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallisation of magma below Earth's surface. Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles, and other minerals. This mineral composition usually gives granite a red, pink, grey, or white color with dark mineral grains visible throughout the rock.
Granite is formed within the crust of the Earth when Felsic magma, that is magma that is rich in Silica, cools down without reaching the surface. Because it remains beneath the surface as it is cooling it forms large crystals (ie, you can see the individual crystals without need of a microscope or hand-lens)