Rock & Mineral Encyclopedia

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

Metagabbro

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

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

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

Fossil wood replaced by opaline silica that preserves wood grain, occasionally showing the play-of-color of precious opal.

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

A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.

A banded jasper showing parallel ribbon-like stripes of contrasting color formed by layered silica and mineral deposition.

A common opal containing moss- or fern-like mineral inclusions that resemble plants suspended in a pale silica body.