mineral

Bismuth

Bismuth (Bi)

Hardness: 2.25 on Mohs scale; Color: Silver-white naturally, but lab-grown crystals display a rainbow iridescence (pinks, blues, greens, golds) due to thin-film oxidation; Luster: Metallic; Crystal Structure: Trigonal / Hopper crystals with stepped, geometric structures; Cleavage: Perfect in one direction;…

Hardness: 2
Luster: Metallic

Identified July 24, 2026More mineral →

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Physical properties

Formation & geological history

Natural bismuth occurs in hydrothermal veins and pegmatites, often associated with lead, copper, tin, and silver ores. However, these distinct hopper-shaped geometric iridescent crystals are artificially grown by melting high-purity bismuth metal and allowing it to cool slowly.

Uses & applications

Used in pharmaceuticals (e.g., Pepto-Bismol), non-toxic lead replacements in bullets and fishing sinkers, cosmetics, low-melting alloys, decorative displays, and mineral collections.

Geological facts

Bismuth is one of the most strongly diamagnetic metals and has one of the lowest thermal conductivities among metals. Although technically radioactive, its isotope Bismuth-209 has a half-life of 19 trillion billion years—over a billion times longer than the estimated age of the universe!

Field identification & locations

Instantly recognizable by its 'hopper' crystal habit (geometric, stepped pyramid-like structures) and striking iridescent rainbow oxidation layer. While natural bismuth is rare and usually massive/dull, laboratory-grown specimens are popular, widely available, and highly decorative.