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