mineral

Bismuth

Bismuth (Bi)

Hardness: 2.25 on Mohs scale, Color: Silver-white with a reddish tint, often showing iridescent oxidation colors (rainbow), Luster: Metallic, Crystal System: Trigonal, Cleavage: Perfect in one direction, Specific Gravity: 9.78

Hardness: 2

Identified July 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and pegmatites, often associated with tin, lead, and silver ores. Naturally occurring native bismuth is rare, but laboratory-grown or synthetic crystals are common in the collector market.

Uses & applications

Used in metallurgy, pharmaceuticals (e.g., Pepto-Bismol), cosmetics, low-melting solders, and as a non-toxic replacement for lead in various applications. Highly popular among mineral collectors for its hopper crystal structure and iridescent colors.

Geological facts

Bismuth is one of the few elements whose liquid state is denser than its solid state, meaning it expands when it freezes, much like water. The vibrant rainbow colors are caused by a thin layer of bismuth oxide forming on the surface when exposed to air.

Field identification & locations

Easily identified by its high density (heavy for its size) and distinct hopper crystal structure with stair-step patterns and iridescent colors. Found worldwide in hydrothermal deposits, with notable commercial mining in China, Mexico, and Peru.