Rock & Mineral Encyclopedia

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

Pelitic Schist

A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.

One of the two jade minerals, an amphibole prized for its extreme toughness and soft, waxy green hues used in carving for millennia.

A rare black carbon-rich rock from Russia, noted for containing fullerenes and ranging from dull mineralized stone to lustrous noble shungite.

A vivid yellow-and-black banded stone from Indonesian volcanic vents, colored by sulfur, arsenic minerals and iron oxides, not true jasper.

A calc-silicate rock formed by chemical exchange between magma and carbonate rock, often rich in garnet and economically important ore minerals.

A pale rock made almost entirely of the sodium feldspar albite, formed by sodic magmatism or sodium metasomatism.

A variety of pyroxenite composed of both orthopyroxene and clinopyroxene with little olivine, found in layered intrusions and the mantle.

A rare, dense iron-rich metamorphic rock composed of fayalite, iron pyroxene, and almandine garnet.

Sand-grained limestone composed of carbonate particles such as shell fragments and ooids cemented into a calcite rock.

A hard, pistachio-green rock composed mainly of epidote and quartz, formed by hydrothermal alteration of mafic rocks.

A coarse-grained, feldspar-free plutonic rock composed mainly of nepheline and sodic pyroxene, the intrusive equivalent of nephelinite.

An old name for cesium-rich, often pink beryl (related to morganite), named after Russian mineralogist Victor Vorobyev.

The colorless to milky-white variety of beryl, known mineralogically as goshenite and once used to imitate diamond and other gems.