A very hard mineral composed of silica, SiO2, found worldwide in many different types of rocks, including sandstone and granite.Varieties of quartz include agate, chalcedony, chert, flint, opal, and rock crystal.

• 石英由硅石组成的一种非常坚硬的矿物质，SiO2，广布世界各地，存在于许多不同种类的岩石中，包括沙岩和花岗岩。石英种类包括玛瑙、玉髓、黑矽石、燧石、蛋白石及水晶