Rock & Mineral Encyclopedia

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

Charoite

A rare swirling lilac-to-violet silicate found only in Siberia, prized for its fibrous, chatoyant purple patterns.

An opaque green variety of chalcedony quartz colored by iron and chlorite-group inclusions, prized as a durable carving and cabochon stone.

The pure colorless variety of beryl, valued as crystal specimens and as a brilliant alternative to clearer gemstones.

The hardest known natural material, a crystalline form of pure carbon prized as the ultimate gemstone for its brilliance and fire.

A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.

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

Rose quartz that displays a six-rayed star (asterism) when cut as a cabochon, caused by microscopic rutile-like inclusions.

Beryl displaying chatoyancy, a bright moving band of light, caused by parallel tube-like inclusions when cut as a cabochon.

Tourmaline displaying chatoyancy, a moving band of light caused by parallel tube-like inclusions, when cut as a cabochon.

Basalt that has been metamorphosed, developing new minerals like chlorite, actinolite, and epidote that give it a greenish color.

Aquamarine that shows a bright moving band of light, or cat's eye, caused by parallel needle-like inclusions when cut as a cabochon.

A vivid Australian jasper-like silica stone in earthy reds, yellows, and purples, formed from silicified radiolarian sediment.

A copper-iron sulfide ore famous for its iridescent peacock-like purple and blue tarnish; often sold as treated chalcopyrite.

A trademarked deep purple-red rhodolite garnet from India, named for its rich grape-like color from the pyrope-almandine series.