Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Black Onyx

A solid jet-black chalcedony, usually a dyed and treated agate, prized for sleek polished beads, cabochons, and intaglios.

A banded variety of chalcedony quartz, classically black or black-and-white, long favored for cameos and beads.

A deep black variety of banded chalcedony, often closely related to or treated like onyx, used for jewelry and carvings.

A banded chalcedony combining reddish-brown sard with white or black onyx layers, prized since antiquity for carved cameos.