Coarse-or medium-grained intrusive rock that is rich in quartz and alkali feldspar .
One of the most common rocks of the Earth's crust, it is formed by the cooling of magma . Granite was once used extensively as paving blocks and building stone, but today its principal uses are as roadway curbing, veneer for building faces, and tombstones. Granite characteristically forms irregular masses of extremely variable size, ranging from less than 5 mi (8 km) in maximum dimension to larger masses ( batholith s) that are often hundreds of square miles in area.