Rock & Mineral Encyclopedia

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

Carnelian

A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.

A bright, opaque-to-translucent bubblegum-pink elbaite tourmaline, a playful candy-pink variety popular in beads and cabochons.

A translucent common opal from the Andes prized for its serene blue to blue-green color, usually cut into cabochons and beads.

Sand-grained limestone composed of carbonate particles such as shell fragments and ooids cemented into a calcite rock.