Flinty Slate

Flinty Slate is an impure quartz, assuming a slaty structure. It contains about 75 per cent. of silica, the remainder being lime, magnesia, oxide of iron, &c. Its fracture is rather splintery than shell-like. It is more or less translucent. It passes by insensible gradations into clay-slate, with which it is often in most intimate geological connection. Lydian Stone (q.v.) is a variety of flinty slate.