Rock & Mineral Encyclopedia

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

Vogesite

A dark hornblende-rich lamprophyre dike rock with amphibole and augite phenocrysts in an alkali-feldspar-dominated groundmass.

Rare precious opal from Tintenbar in northern New South Wales, Australia, occurring in volcanic basalt rather than sedimentary rock.

A hard zinc-rich member of the spinel group, usually dark blue-green to black, forming octahedral crystals in metamorphic and pegmatitic rocks.

A rare chlorine-bearing iron garnet-supergroup mineral, the ferric analogue of wadalite, formed in high-temperature combustion-metamorphic rocks.