Rock & Mineral Encyclopedia

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

Chrysoprase

A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.

The blue-green gem variety of microcline feldspar, often mottled with white, prized as an affordable ornamental stone.

A green, gold-associated metamorphic rock made of chrome-rich mica and quartz, named for Mariposa County in California's gold country.

A foliated metamorphic rock dominated by quartz with enough mica to give it a schistose, splitting fabric.

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