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