Rock & Mineral Encyclopedia

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

Charnockite

A granite-like rock containing orthopyroxene, formed at high temperatures and pressures and often classed with the granulites.

A dark, foliated schist rich in graphite that leaves a grey-black mark and forms from metamorphosed carbon-rich sediments.

A hydrated volcanic glass with pearly, onion-like concentric cracks that pops into lightweight white granules when heated.

A feldspar gem famous for adularescence, a floating blue-white glow that shimmers across the stone like moonlight.

A general term for light-colored, fine-grained volcanic rocks rich in quartz and feldspar, like rhyolite.