Rock & Mineral Encyclopedia

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

Turquoise

A prized blue to blue-green copper-aluminium phosphate, often veined with dark matrix, treasured for jewelry across many cultures.

A vivid turquoise-blue glass sold as obsidian; this bright color is virtually always manufactured rather than natural volcanic glass.

A common opal colored green by nickel or chromium impurities, usually opaque and cut into cabochons and beads.

A vivid green copper carbonate mineral famous for swirling concentric bands, used as an ore of copper and an ornamental gemstone.

A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.