Rock & Mineral Encyclopedia

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

Mustard Jasper

A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.

A warm-toned jasper named for its autumn-leaf palette of browns, rust, gold, and cream, popular as soothing earth-tone beads.

A soft-toned cream-to-butterscotch jasper colored by iron oxides, prized by lapidaries for its smooth, even, opaque finish.

A soft-toned, multicolored jasper with swirling green, mauve, and cream patterns, popular and affordable in the bead trade.

A black volcanic glass speckled with gray-white cristobalite snowflakes, formed as obsidian begins to crystallize.

A rare opal whose play-of-color appears only when light passes through it, glowing best when backlit or held to the light.

A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.

A water-bearing massive grossular garnet, usually green or pink, widely used as a tough jade-like carving stone.