BISMUTHINITE
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.