chertCHERT, n. In mineralogy, a subspecies of rhomboidal quartz; called also hornstone, petrosilex or rock flint. It is less hard than common quartz; its fracture usually dull and splintery, sometimes more or less conchoidal. It is more or less translucent, sometimes at the edges, and sometimes the whole mass, if thin, has the strong translucency of certain horns. Its colors are numerous and usually dull. It is usually amorphous, sometimes globular, or in nodules. It occurs often in veins, especially metallic, in primitive mountains. |