Rock & Mineral Encyclopedia

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

Chalcopyrite

A brassy copper-iron sulfide that is the world's most important copper ore, often showing colorful iridescent tarnish.

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

The pure colorless variety of beryl, valued as crystal specimens and as a brilliant alternative to clearer gemstones.

The colorless variety of beryl, named after Goshen, Massachusetts, prized for its purity, clarity, and durability.