Rock Identifier
Bismuth crystal (Bismuth (Bi), synthetic laboratory-grown crystal) — mineral
mineral

Bismuth crystal

Bismuth (Bi), synthetic laboratory-grown crystal

AI-generated identification · may be incorrect

Metallic luster with strongly iridescent oxide colors—often green, blue, gold, and pink—and distinctive stepped, hopper-shaped crystals; Mohs hardness 2–2.5, orthorhombic crystal structure, brittle, specific gravity about 9.8. The specimen appears to be a cluster of fused, artificially crystallized masses.

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Physical properties

Metallic luster with strongly iridescent oxide colors—often green, blue, gold, and pink—and distinctive stepped, hopper-shaped crystals; Mohs hardness 2–2.5, orthorhombic crystal structure, brittle, specific gravity about 9.8. The specimen appears to be a cluster of fused, artificially crystallized masses.

Formation & geological history

Usually made by melting refined bismuth and allowing it to cool slowly, producing hopper crystals; it is human-processed rather than a naturally collected geological formation. Natural bismuth occurs in hydrothermal veins associated with tin, tungsten, lead, and silver deposits.

Uses & applications

Primarily sold as a decorative mineral specimen, educational display, or collector piece; bismuth is also used in low-melting alloys, pharmaceuticals, cosmetics, and lead-free ammunition. It is generally not used as a gemstone.

Geological facts

The rainbow coloration is a thin-film oxide coating formed during cooling or subsequent exposure to air, not the intrinsic color of bismuth. Hopper faces develop because crystal edges grow faster than central surfaces.

Field identification & locations

Identify it by its heavy weight, very low hardness, brittle metallic texture, and geometric stair-step cavities; it is nonmagnetic and melts at only about 271°C. Common specimens are produced commercially worldwide, especially in China and the United States.