Rock & Mineral Encyclopedia

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

Orange Calcite

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.