Rock & Mineral Encyclopedia

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

Stibnite

Stibnite is the chief ore of antimony, famous for its dramatic clusters of bladed, silvery-gray metallic crystals.

A silver sulfide that is one of the most important silver ore minerals, forming dark metallic crystals and wires.

A black metallic silver antimony sulfide, historically a notable silver ore known as brittle silver ore.

A metallic cobalt-nickel arsenide, an important cobalt ore, named for the Skutterud mines of Norway.

Chromite is the only commercial ore of chromium, a black iron-chromium oxide of the spinel group found in mafic igneous rocks.

A silver-white cobalt arsenic sulfide that is a leading ore of cobalt, forming bright metallic cubic and pyritohedral crystals.

Ilmenite is the world's leading source of titanium, a heavy iron-black oxide common in mafic rocks and black sands.

A calcium- and ferrous-iron-rich tourmaline, the iron analogue of uvite, forming dark brown to black crystals in skarns and metamorphic rocks.

A rare ultrapotassic, magnesium-rich volcanic rock from deep in the mantle, famous as the diamond host at Argyle in Australia.