Quartzite is a natural and metamorphic stone, that in other words, formed from the modifications of other stones or minerals, in this case, sandstone rich in quartz. Hence, quartzite stone is composed of approximately 90% quartz.
Quartzite begins its geological life as grains of sand. Over time these sand grains are compressed and stick together to form sandstone. This sandstone is buried deeper and deeper under layers of rock and is heated and compressed. The deeper it goes, the more pressure and heat there is, so that the quartz grains in the sandstone lose their original shape and form a dense, hard rock.
These stones are then quarried and cut into slabs to be used for countertops, cladding, etc.