Rock & Mineral Encyclopedia

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

Diamond

The hardest known natural material, a crystalline form of pure carbon prized as the ultimate gemstone for its brilliance and fire.

A natural zirconium silicate gem with high brilliance and fire, often confused with the synthetic imitation cubic zirconia.

A colorless, transparent variety of topaz valued as an affordable, hard, brilliant alternative to diamond in jewelry.

A rare ultramafic volcanic rock that erupts from deep in the mantle and is the primary natural source of diamonds.

A synthetic garnet-structured oxide (YAG) used as a diamond simulant and laser crystal, with no natural counterpart.

Exceptionally clear, naturally double-terminated quartz crystals from Herkimer County, New York, prized for their diamond-like brilliance.

A rare translucent yellow-green volcanic glass from the Macusani region of Peru, valued by faceters and sometimes confused with tektites.

A rare agate that forms naturally with flat polygonal faces and angular geometric shapes rather than the usual rounded nodule.