Rock & Mineral Encyclopedia

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

Marble

A metamorphosed limestone of interlocking calcite crystals, prized for sculpture and architecture for its workability and polish.

An extremely hard metamorphic rock formed from sandstone, made of fused quartz grains that break across rather than between the grains.

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

A black volcanic glass threaded with delicate grey, swirling lace-like bands of flow lines that show beautifully when polished.