Rock & Mineral Encyclopedia

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

Lamproite

A rare ultrapotassic, magnesium-rich volcanic rock from deep in the mantle, famous as the diamond host at Argyle in Australia.

Fossil shells whose original material has been replaced by opal, preserving ancient marine forms in common or precious opal.

An opal cut to show chatoyancy, a sharp moving band of light like a cat's eye, usually in honey, green or yellow common opal.

A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.

A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.