Rock & Mineral Encyclopedia

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

Cuprite

Cuprite is a deep red copper oxide and an important secondary copper ore, prized for its rare ruby-red gem crystals.

A copper-iron sulfide ore famous for its iridescent peacock-like purple and blue tarnish; often sold as treated chalcopyrite.

A vivid copper-bearing Mexican stone of red cuprite and green chrysocolla that evokes a desert sunset.

A rare, intensely blue chalcedony colored by copper-rich chrysocolla, prized as the most valuable of the blue chalcedonies.

A copper-bearing labradorite feldspar from Oregon, famous for its range of natural colors and glittery aventurescent copper schiller.

Tourmaline colored by copper, producing the famous vivid neon blues, greens and teals known commercially as Paraiba-type gems.

An intensely glowing copper-bearing tourmaline whose electric neon-blue color makes it one of the most valuable gems in the world.

An intensely glowing copper-bearing tourmaline famed for its electric neon blue-green color and extreme rarity and value.

A dark gray copper sulfide that is one of the richest copper ores, prized by collectors when found as rare sharp crystals.

An earthy aluminum-rich residual rock and the world's principal ore of aluminum, often showing distinctive pea-like pisolites.