Bismuthinite is a scarce bismuth sulfide mineral (Bi2S3).  It's similar to stibnite in its physical properties, and fine-grained specimens are difficult to distinguish visually.  Bismuthinite has a metallic luster, silver color, gray streak, one perfect cleavage, is fairly soft (H = 2 to 2.5), and has a high specific gravity (it's heavy for its size).  Nicely crystalline specimens often display radiating masses of long, needle-shaped crystals.  Finer-grained and massive bismuthinite also occur.  Crystals of bismuthinite are known to be slightly flexible, and the crystal faces typically have fine striations.


Bismuthinite is a key ore mineral for the element bismuth (Bi).  It principally occurs in hydrothermal vein deposits, some pegmatites, and some volcanic exhalation deposits.


Bismuthinite (silver-colored areas) in pegmatitic granite with quartz (glassy gray material in lower part) & K-feldspar (cream/buff-colored material at upper left) (3.4 cm across at its widest).

Geology: pegmatite body in the Preissac-Lacorne Batholith (Abitibi Greenstone Belt, late Neoarchean, 2.630-2.675 billion years).

Locality: Moly Hill, Quebec, Canada.



Photo gallery of bismuthinite



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