Rock & Mineral Encyclopedia

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

Red Agate

A red-toned banded chalcedony colored by iron oxides, ranging from natural carnelian-like reds to heat-treated stones.

A precious opal pattern made of tiny, densely packed pinpoint flashes of play-of-color, like sparkling speckles across the stone.

Obsidian formed from two merged lava flows, producing a stone with two distinct bands of sheen or color.

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.