Quartz

Quartz is the second abundant mineral in the Earth’s Crust. It is made of the two most abundant chemical elements on Earth: oxygen and silicon. It is found in all forms of rock: igneous, metamorphic and sedimentary. Quartz is physically and chemically resistant to weathering. When quartz-bearing rocks become weathered and eroded, the grains of resistant quartz are concentrated in the soil, in rivers, and on beaches. The white sands typically found in river beds and on beaches are usually composed mainly of quartz, with some white or pink feldspar as well. Today, billions of quartz crystals are used to make oscillators for watches, clocks, radios, televisions, electronics games, computers, cell phones, electronic meters and GPS equipment. Many varieties are gemstones, including amethyst, citrine, smoky quartz and rose quartz. Large amounts of quartz sand are used in the manufacture of glass and ceramics and for foundry molds in metal casting.