mineral

Bismuth Crystal

Bismuth (Bi)

Hardness: 2.25 on Mohs scale; Color: Silver-white base with iridescent rainbow oxidation; Luster: Metallic; Crystal Structure: Trigonal (often featuring hopper growth); Cleavage: Perfect; Specific Gravity: 9.78

Hardness: 2
Color: Silver-white base with iridescent rainbow oxidation
Luster: Metallic

Identified April 2, 2026More mineral →

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Physical properties

Formation & geological history

While bismuth occurs naturally in the Earth's crust (hydrothermal veins and pegmatites), the colorful 'hopper' crystals shown are lab-grown by melting high-purity bismuth and allowing it to cool slowly, forming an iridescent oxide layer upon contact with air.

Uses & applications

Used in metallurgy as a lead substitute, in pharmaceuticals (like Pepto-Bismol), in cosmetics (bismuth oxychloride), and as popular collector's specimens and jewelry pieces.

Geological facts

Bismuth is one of the few substances, like water, that expands as it freezes from a liquid to a solid. It is also the most naturally diamagnetic element and has low toxicity compared to neighboring heavy metals like lead or antimony.

Field identification & locations

Identify in the field/lab by its unique 'stair-step' hopper crystal shape and rainbow tarnish. Natural bismuth is rare and usually looks like dull metallic lumps, whereas these vibrant geometric crystals are almost exclusively human-made.