The two main constituents of granite are feldspar and quartz. The chemical composition of granite usually constitutes silica (70-77 percent), alumina (11-13 percent), potassium oxide (3-5 percent), soda (3-5 per cent), lime (1 percent), total iron (2-3 per cent) and magnesia and titania (less than 1 percent). The volcanic rock with chemical composition and mineralogy equivalent to granite is called rhyolite. Granites are the most abundant type of plutonic rocks which are found mainly in the mountain belts and continental shield regions. They occur in great batholiths which occupy thousands of square kilometres. Granites are usually associated with minerals like quartz monzonite, granodiorite, diorite, and gabbro.