Quartz is a hard, crystalline mineral composed of silicon and oxygen atoms. Quartz is the second most abundant mineral in the Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral.

There are many different varieties of quartz, several of which are semi-precious gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia.

Quartz was the mineral upon which the Stone Ages were based. With few exceptions, earliest stone tools were fashioned of quartz.

Uses:

• It is used as oscillators in radios.
• Watches.
• Pressure gauges.
• In the study of optics.