Rock & Mineral Encyclopedia

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

Tiger Iron

A banded combination rock of golden tiger's eye, red jasper, and metallic hematite, formed in ancient iron deposits.

An affordable multicolored banded and mossy chalcedony from India, common in tumbled stones, beads, and meditation pieces.

The gem variety of corundum in every color except red, most prized in velvety blue and exceptionally hard and durable.

Soft pastel-colored glass sold as obsidian; multicolor pastel material is manufactured art glass rather than natural volcanic obsidian.

A mottled, multicolored obsidian blending black, brown, grey, and tan patches like a calico cat's patchwork coat.

A natural sheen obsidian combining a bright silver shimmer with iridescent peacock colors, all produced by nanoparticle layers in black glass.

Tourmaline showing many color zones in a single crystal, often revealing spectacular concentric patterns when sliced.

Tourmaline displaying two distinct colors in a single crystal, a natural color-zoning effect that makes each stone unique.

Precious opal that displays a broad, vivid sweep of spectral colors, flashing the full rainbow as it is tilted in the light.

Tourmaline displaying three distinct color zones in a single crystal, a striking natural result of changing growth chemistry.