mineral

Iridescent bismuth crystal

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

AI-generated identification · may be incorrect

Metallic luster with vivid pink, purple, blue, and green iridescence from a thin oxide film; Mohs hardness 2–2.5, brittle, dense (specific gravity about 9.8), and typically displays hopper-shaped stepped crystals. The specimen appears artificially grown and surface-oxidized rather than naturally weathered.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Bismuth crystals form as molten bismuth cools slowly, producing skeletal hopper growth; the colors develop through controlled oxidation. Most retail specimens are modern laboratory-grown pieces, not products of a specific geological age.

Uses & applications

Primarily sold as a decorative mineral and collector specimen; occasionally used for demonstrations of crystal growth. Bismuth has industrial applications in low-melting alloys, pharmaceuticals, pigments, and lead-free materials.

Geological facts

Its rainbow colors are optical interference effects, not the intrinsic color of metallic bismuth. Bismuth is notably diamagnetic and expands slightly on solidification.

Field identification & locations

Identify it by its extreme density, brittle metallic texture, stepped hopper geometry, and intense oxide rainbow; it should not be confused with natural bornite (“peacock ore”). Commonly produced in China and laboratories worldwide.