Granite is igneous stone (produced from intense heat). It started as liquid magma from the depths of the earth. Under extreme pressures and a slow cooling process, granite is one of the hardest and most dense types of stone. It is made up of many components with the most common being quartz, mica, and feldspar. The amount of these components can greatly vary for each type of granite. Usually feldspar is the major mineral of granite.
Secondly is quartz. Quartz is the hardest mineral in the composition of the stone. In comparison to a diamond, quartz is approximately 75% as dense.