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Chemical Formula | Bi |
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Composition | Bismuth, usually with traces of arsenic, antimony, and sulfur |
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Variable Formula | (Bi,As,Sb,S) |
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Color | Silver-white, sometimes with reddish hue. Oxidizes yellowish to dark gray |
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Streak | Silver-white |
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Hardness | 2 - 2½ |
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Crystal Forms and Aggregates |
(Hexagonal) Crystals are rare, and are usually flat hexagons occurring in parallel groupings. Pseudocubic, hopper-like crystal groupings are almost never found in nature, but are easily grown. Bismuth also occurs massive. |
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Transparency | Opaque |
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Specific Gravity | 9.7 - 9.8 |
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Luster | Metallic |
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Cleavage | 2,1 - prismatic ; 3,1 - basal |
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Fracture | Hackly to uneven |
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Tenacity | Brittle and slightly sectile |
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Other ID Marks | 1) Tarnishes yellow to dark gray 2) Usually striated on cleaved surfaces |
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Other Names |  Native Bismuth |
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In Group | Native elements ; Semi-metallic elements |
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All About | Bismuth is about as rare as Silver. Bismuth has a metallic-white
color with a slight reddish or pinkish hue. Such a color
will only be present on an untarnished (i.e. freshly
broken) surface, since Bismuth tarnishes yellow to
dark-gray. Bismuth rarely occurs in decent crystals. Most marketed Bismuth specimens are man made, and exhibit a very interesting shape. They have hopper-like growths in pseudocubic crystals, and are usually coated with chemicals to prevent tarnish, thus maintaining the silver-white color. |
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Uses | Bismuth is an ore
of the element bismuth. Much of the poor quality Bismuth
specimens are artificially regrown to produce
interestingly shaped hopper-like Bismuth specimens. Bismuth has a very interesting property: Similar to water, instead of contracting when it solidifies, like all other matter, it expands. This, and the fact that it is very diamagnetic, offer it numerous uses in the electronic field. |
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Striking Features | Color, tarnish, sectility, and striations on cleaved surfaces |
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Complex Tests | Becomes slightly malleable when heated, expands when solidifying, and is strongly diamagnetic |
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Popularity (1-4) | 2 |
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Prevalence (1-3) | 4 |
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Demand (1-3) | 2 |
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Distinguishing Similar Minerals |
Antimony, Arsenic - lighter (5.6 - 5.7 and 6.6 -
6.7), harder (3 - 3½ and 3½) Tellurium - lacks reddish hue, lighter color, less dense (6.1 - 6.3) |
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Commonly Occurs With |
Bismuthinite, Cassiterite |
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Noteworthy Localities |
Probably the best specimens were taken from Schneeberg and Saxony, Germany. Excellent specimens were also found in Fahlun, Sweden, and at San Baldomero, near La Paz, Bolivia.. In Canada, it has been found at Cobalt, Timiskaming District, Ontario, and at Great Bear Lake, Mackenzie District, Northwest Territory. It occurs with Bismuthinite in the El Carmen Mine in Durango, Mexico. No U.S. locality is really noteworthy, although small amounts have been found in California, South Carolina, and South Dakota. |
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Picture Icon Links |
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Picture Links | Sorry. No Images currently available. |
