Bismuth Crystal

Physical Properties

Hardness: 2.0-2.5 on Mohs scale. Color: Iridescent multicolor (caused by oxidation) over a silver-white base. Luster: Metallic. Crystal structure: Trigonal (often forming hopper crystals). Cleavage: Perfect on {0001}. Specific gravity: 9.78.

Formation & Geological History

Laboratory-grown through a slow cooling process of molten high-purity bismuth metal. Natural bismuth occurs in hydrothermal veins and pegmatites, but rarely in this iridescent hopper form.

Uses & Applications

Used primarily as a collector's specimen and in jewelry. Industrially, bismuth is used in cosmetics (bismuth oxychloride), pharmaceuticals (Pepto-Bismol), and low-melting alloys/solders.

Geological Facts

The iridescent colors are caused by a thin layer of bismuth oxide on the surface; light reflects off the top and bottom of this layer to create constructive interference. Despite being a heavy metal, it is non-toxic and is the most naturally diamagnetic element.

Field Identification & Locations

Identify by its unique 'hoppered' staircase crystal structure and vibrant rainbow iridescence. In nature, bismuth is typically massive or granular and lacks these bright colors.

Identified on: 4/30/2026

Mode: Standard