Rock & Mineral Encyclopedia

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

Dunite

An ultramafic intrusive rock made almost entirely of olivine, representing mantle material.

A dense, coarse-grained ultramafic rock rich in olivine that makes up most of the Earth's upper mantle.

A depleted mantle peridotite of olivine and orthopyroxene, the refractory residue left after basaltic melt is extracted from the mantle.

An ultramafic rock of olivine and clinopyroxene, a peridotite variety common as cumulate layers in mafic intrusions.

The most common type of mantle peridotite, made of olivine with both orthopyroxene and clinopyroxene, representing fertile upper-mantle rock.

The gem-quality green variety of olivine, peridot is colored by iron and is one of the few gems found in only one color.