| Chert is a hard, compact, dense, brittle rock which
generally varies in colour from white, through light grey to dark grey. The appearance is
waxy and smooth; quartz,
with which chert might be confused, is glassy. When struck with a hammer, chert breaks
with a conchoidal fracture,
like broken glass, or shatters into splinters. These properties result because chert
consists of very fine-grained silica. Chert occurs as nodules or irregular bands in limestone, or as thin beds or
ribbon-shaped layers separated by thin films of shale. |
