mineral

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxide-coated

AI-generated identification · may be incorrect

Metallic luster with vivid rainbow iridescence from a thin bismuth-oxide film; distorted hopper crystal structure, brittle, Mohs hardness 2–2.5, specific gravity about 9.8. The stepped, skeletal geometry and metallic rainbow colors are characteristic.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Usually a human-grown specimen formed by melting high-purity bismuth and allowing it to cool slowly; natural bismuth crystallizes in hydrothermal veins, commonly associated with tin, tungsten, lead, and silver ores. The visible coloration is generally an artificial surface oxidation effect, not natural gemstone color.

Uses & applications

Collected as a display mineral and used in demonstrations of crystal growth; bismuth alloys have applications in low-melting solders, pharmaceuticals, and environmentally preferable metals. It has little jewelry value because it is soft and brittle.

Geological facts

Bismuth is one of the heaviest naturally occurring elements and is weakly diamagnetic. Its rainbow appearance comes from interference within the oxide coating, which can fade or abrade with handling.

Field identification & locations

Identify by its extremely heavy feel, metallic sheen, brittle stepped hopper crystals, and iridescent oxidation colors; it should not be confused with similarly colored coated quartz or glass. Common specimens are laboratory products sold worldwide.