Rock & Mineral Encyclopedia

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

Starburst Agate

Agate containing radiating sprays of mineral needles that fan out like bursting stars within the chalcedony.

An opaque to translucent milky-white common opal valued for its soft porcelain-like color rather than play-of-color.

A precious opal showing dominant peacock-like blue, green and teal play-of-color, often on Ethiopian material.