Rock & Mineral Encyclopedia

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

Honey Calcite

A warm golden-to-amber variety of calcite, a soft calcium carbonate mineral valued for its honeyed glow and easy carving.

A soft, glowing orange variety of calcite colored by iron oxides, popular as tumbled stones and known for fizzing in acid.

Calcium-carbonate sedimentary rock packed with visible fossils, recording ancient marine life within an easily scratched, fizzing matrix.

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

A soft, porous limestone made of loosely cemented shell and coral fragments, used as a coastal building stone.

A soft, colorful calcium fluoride mineral famous for cubic crystals, perfect octahedral cleavage, and fluorescence under UV light.

An opal cut to show chatoyancy, a sharp moving band of light like a cat's eye, usually in honey, green or yellow common opal.