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.

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

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

A natural zirconium dioxide mineral, hard and refractory, valued as a zirconium source and prized for high-precision U-Pb dating.

The brassy iron sulfide mineral famous as 'fool's gold,' known for sharp metallic cubes and a much higher hardness than real gold.

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

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

A translucent yellow-green silicate famous for its botryoidal 'grape' clusters, often hosting needle-like sprays of black epidote.

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

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

A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.

A rare manganese-bearing hydrogarnet notable for being tetragonal rather than cubic, found in metamorphosed manganese deposits in Morocco.

A rose-pink manganese silicate marbled with black veins, prized as a tough ornamental and occasionally faceted gemstone.