Rock Identifier
Native bismuth (Bismuth (Bi), commonly artificially crystallized) — mineral
mineral

Native bismuth

Bismuth (Bi), commonly artificially crystallized

AI-generated identification · may be incorrect

Metallic silver-white to iridescent tarnish, very high density (about 9.8 g/cm³), Mohs hardness 2–2.5, brittle, with a rhombohedral crystal structure and poor cleavage. The stepped, hopper-like form and rainbow oxide coating are characteristic of lab-grown bismuth crystals.

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Physical properties

Metallic silver-white to iridescent tarnish, very high density (about 9.8 g/cm³), Mohs hardness 2–2.5, brittle, with a rhombohedral crystal structure and poor cleavage. The stepped, hopper-like form and rainbow oxide coating are characteristic of lab-grown bismuth crystals.

Formation & geological history

Native bismuth occurs in hydrothermal veins associated with tin, tungsten, and lead ores, forming at relatively low temperatures; most dramatic specimens sold commercially are remelted and recrystallized from purified bismuth. Geological examples are found in deposits from hydrothermal systems of various ages.

Uses & applications

Used industrially in low-melting alloys, free-machining steels, pharmaceuticals, pigments, and lead-free solders; attractive crystals are popular mineral specimens. It is generally unsuitable for jewelry because it is soft and brittle.

Geological facts

Bismuth is one of the heaviest naturally occurring elements and has unusually low toxicity compared with lead. Its oxide-film colors are surface interference effects, not the crystal’s intrinsic color.

Field identification & locations

Identify by exceptional weight, brittleness, metallic luster, and hopper/stepped crystals with iridescent tarnish; distinguish from galena, which is harder and forms cubic crystals. Common localities include Bolivia, Peru, China, Germany, and Canada.