Rock & Mineral Encyclopedia

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

Serpentinite

A green, often mottled metamorphic rock formed by the hydration of mantle rocks, soft and waxy with a smooth, slippery feel.

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.

Basalt that has been metamorphosed, developing new minerals like chlorite, actinolite, and epidote that give it a greenish color.

A general field term for green, low-grade metamorphosed basaltic rocks colored by chlorite, epidote, and actinolite.

A metamorphic rock of calcium-rich silicate minerals formed from impure limestone or dolomite altered by heat and fluids.

A tough, dark, medium-grained igneous rock with the composition of basalt, common in dikes and sills.

Rhyolite that has been metamorphosed, recrystallizing its silica-rich volcanic material into a tougher felsic metamorphic rock.

Coarse-grained gabbro that has been metamorphosed, partly recrystallizing into amphibole, plagioclase, and other metamorphic minerals.

A dark, dense metamorphic rock dominated by hornblende and plagioclase, formed by medium- to high-grade metamorphism of basalt.

An altered granite of pink feldspar, green epidote and quartz, mottled pink-and-green and popular as a tumbled and carving stone.

An altered granite mottled pink and green from feldspar and epidote, popular as a tough, colorful ornamental rock.

A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.

A soft, green, foliated rock rich in chlorite, formed by low-grade metamorphism of mafic or volcanic rocks.

A vivid green hydrous nickel-magnesium silicate that is a major ore of nickel, mined from weathered ultramafic rocks.