Rock & Mineral Encyclopedia

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

Onyx Marble

Translucent banded calcium-carbonate stone deposited in caves and springs, prized for ornamental carvings despite its softness.

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

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

The classic agate defined by concentric or parallel bands of chalcedony in varied colors, the archetype of all agate varieties.

A green-and-white banded metamorphic marble whose wavy mica layers resemble the rings of a sliced onion.

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.

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

A banded chalcedony with straight, ribbon-like parallel layers, often cut across the bands for striking striped cabochons.

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

A banded, porous limestone deposited by mineral springs, prized as a warm-toned natural building and tile stone.

A soft, fine-grained, translucent form of gypsum (or banded calcite) long prized as a carving and ornamental stone.