 |
|
|
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 is not a common mineral and usually occurs in uninteresting forms. It rarely occurs in decent crystals. Bismuth is about as rare as Silver.
Most marketed Bismuth specimens are laboratory grown, 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. Sometimes the coating gives a colorful effect on the bismuth. These artificial crystals are very often sold to collectors without being specified that they are lab grown. Any hopper-shaped crystal with a fine luster and no tarnish should be assumed to be artificial.
|
|
|
|
Chemical Formula |
Bi |
|
Composition |
Bismuth, usually with traces of arsenic, antimony, and sulfur |
| Variable Formula |
(Bi,As,Sb,S) |
|
Color |
Silver-white, sometimes with reddish hue. Oxidizes yellowish to dark gray. |
|
Streak |
Silver-white |
|
Hardness |
2 - 2.5 |
|
Crystal System |
Hexagonal |
Crystal Forms
and Aggregates |
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 in a lab. Bismuth also occurs massive and as waterworn nugget in stream beds. |
|
Transparency |
Opaque |
|
Specific Gravity |
9.7 - 9.8 |
|
Luster |
Metallic |
|
Cleavage |
2,1 - prismatic ; 3,1 - basal |
|
Fracture |
Hackly to uneven |
|
Tenacity |
Brittle and slightly sectile |
|
Other ID Marks |
1) Tarnishes yellow to dark gray.
2) Usually striated on cleaved surfaces. |
|
Complex Tests |
Becomes slightly malleable when heated, expands when solidifying, and is strongly diamagnetic |
|
In Group |
Native Elements; Semi-Metallic Elements |
|
Striking Features |
Color, tarnish, sectility, and striations on cleaved surfaces |
| Environment |
In mesothermal veins, in hydrothermal replacement deposits, and in granite pegmatites. |
|
Popularity (1-4)
|
2 |
|
Prevalence (1-3)
|
1 |
|
Demand (1-3) |
2 |
|
 |
|
|
|
|
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 for collectors.
Bismuth has a very interesting property in that it expands when it solidifies, unlike all other matter which contracts. (This same property is exhibited in water.) This unique propery, and the fact that it is highly diamagnetic, offer it numerous uses in the electronics field.
|
|
Probably the best specimens were found in Schneeberg and the surrounding areas in the Erzgebirge in Saxony, Germany. Very good specimens have also come from St. Ives, Cornwall, England; Wolfram Camp, Dimbulah, Queensland, Australia; and the Siglo Veinte Mine (Llallagua), Potosi, Bolivia. In Canada, it has been found in and around Cobalt, Timiskaming District, Ontario. It occurs with Bismuthinite in the El Carmen Mine in Durango, Mexico.
|
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)
|
|
|
|
|
|
|
|
Have a question about Bismuth? Visit our Q&A Community and ask the experts!
|
|
|
|
Let us know how we can update this page
(Click for more details)
|
|
We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.
|
 |
| |
|
|
|
|
|
|
|
