Rock & Mineral Encyclopedia

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

Felsite

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

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

A common coarse-grained intrusive rock like granite but richer in plagioclase than potassium feldspar.

A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.

A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.