A coarse-grained igneous rock that has been subjected to metamorphic processes, formed by cooling of silica-rich magma below the surface of the earth at great depths and pressures. It is the most common intrusive acid igneous rock of the Earth's crust. Granite is commonly found on continents, but is virtually absent from the ocean basins. The term "granite" refers to its visible granular composition. It has a visibly crystalline texture, is usually red, whitish, or gray in color depending upon its composition, is very hard and durable, and takes a fine polish. Granite is primarily composed of feldspar, quartz, and mica along with various other minerals in varying percentages. Granite is frequently used for buildings and monuments. 

Source: AAT

http://vocab.getty.edu/page/aat/300011183