1. A very hard, dense, even - textured, silica - bearing sedimentary rock used in whetstones. This is a cliff composed of quartz sandstone that is well bedded. 均密石英岩非常坚硬，致密，结构均匀，含硅的沉积岩，用作磨石由石英砂岩构成的悬崖，岩石层理发育。