From Ohio History Central
Brush Creek Chert.jpg
This sample of Brush Creek chert measures approximately 2.5" x 2.5" (6.35 x 6.35 cm).

Chert is an impure form of flint. Some people believe the opposite --- that flint is a variety of chert. In either case both minerals are varieties of quartz. The name chert is dialectal English; its origin is unknown. The mineral occurs in various colors including white, brown, yellow and gray. Chert is more brittle than flint and cannot be worked as well as flint.

See Also