This article is about the mineral. See Onyx (disambiguation) for other meanings

Onyx is a banded variety of chalcedony, a cryptocrystalline form of quartz. The colours of its bands are white and black. It is usually cut as a cabochon, or into beads, and is also used for intaglios and cameos. Some onyx is natural but much is produced by the staining of agate.

See also

• list of minerals