chert
/tʃɜːt/noun
mass noun
- a hard, dark, opaque rock composed of silica (chalcedony) with an amorphous or microscopically fine-grained texture. It occurs as nodules (flint) or, less often, in massive beds.燧石, 黑硅石。
派生词
cherty
adjective词源
late 17th cent. (originally dialect)： of unknown origin.