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

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.