Rock & Mineral Encyclopedia

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

Quartz Arenite

A clean, mature sandstone made almost entirely of quartz grains, representing extreme weathering, sorting, and recycling of sediment.

A vivid greenish-yellow quartz, usually heat-treated or irradiated, prized for its clean clarity and bright lemon color.

A glassy, jet-black volcanic rock formed when lava cools too fast to crystallize, prized for razor-sharp conchoidal edges.

A rare zirconium-bearing garnet that crystallizes in carbonatites and alkaline rocks, first described from Magnet Cove, Arkansas.