mineral

Bismuth Crystal

Bismuth (Bi)

Hardness: 2.25 on Mohs scale; Color: Silver-white interior with iridescent rainbow oxide layer; Luster: Metallic; Crystal Structure: Rhombohedral (Hopper crystals); Cleavage: Perfect; Specific Gravity: 9.78

Hardness: 2
Color: Silver-white interior with iridescent rainbow oxide layer
Luster: Metallic

Identified July 19, 2026More mineral →

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Physical properties

Formation & geological history

Laboratory-grown through a slow cooling process of molten high-purity bismuth. While bismuth occurs naturally in the Earth's crust (Native Bismuth), these specific geometric 'hopper' crystals are man-made.

Uses & applications

Primarily used as a decorative collector's specimen. Industrial bismuth is used in cosmetics, pharmaceuticals (Pepto-Bismol), low-melting-point alloys, and as a non-toxic replacement for lead in shot and sinkers.

Geological facts

Bismuth is one of the few substances (like water) that expands as it freezes. The iridescent colors are caused by thin-film interference on an oxidation layer; the thickness of the layer determines the color seen.

Field identification & locations

Identify by the unique 'hoppered' staircase-like crystal structure and vibrant rainbow metallic luster. It is much heavier than it looks due to its high density.