Quartz, widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide (SiO2). Large amounts of quartz sand (also known as silica sand) are used in the manufacture of glass and ceramics and for foundry molds in metal casting. Quartz is very resistant to both chemicals and heat. It is therefore often used as foundry sand. Quartz sand finds its wide application in the petroleum industry. Quartz crystals are used to make oscillators for watches, clocks, radios, televisions, electronic games, computers, cell phones, electronic meters, and GPS equipment. Quartz makes an excellent gemstone. Based on the application and customer requirement, quartz can be supplied in specified size. The three main variants are quartz powder, quartz lumps and quartz grits.