Quartz (silicon dioxide, also known by the scientific name α-Quartz) is a mineral widespread in the earth's crust, which has the chemical composition SiO2 crystallizing in the trigonal system.
In its pure state, quartz is colorless, impurities in the crystal determine the color of the mineral. Quartz frequently crystallizes in voids in rocks called geodes. The cleavage is non-existent in the crack having a pearly color, it has the value 7 on the Mohs hardness scale.
Before the discovery of its piezoelectric property, quartz was used as a stone in jewelry.
Pure quartz crystals are colorless, transparent, due to inclusions of gases or liquids, the crystal becomes milky, similarly, impurities cause the color to change, or through irradiation, an ionization phenomenon is produced that changes the color of the crystal.
The most important deposits of white quartz are found in Brazil, Zambia, Pakistan, Sri Lanka, Madagascar.