THE MINERAL BISMUTHINITE

  • Chemistry: Bi2S3, Bismuth Sulfide
  • Class: Sulfides
  • Uses: An ore of bismuth and as mineral specimens.
  • Specimens

Bismuthinite is an important ore of bismuth. Sprays of steel gray prismatic bismuthinite crystals radiate outward from a common attachment point in the more spectacular specimens of this somewhat rare sulfide mineral. These specimens can not help but be compared to specimens of stibnite. It is difficult to distinguish from the similar looking and closely related antimony sulfide. Bismuthinite is heavier than stibnite and on closer inspection of the crystals, there exists a noticeable difference with bismuthinite's having straighter, flatter faces. In massive form the confusion is even more pronounced, but bismuthinite is not associated with the typical antimony or arsenic minerals to which stibnite is so commonly allied.

Associations of bismuthinite are varied, but combinations with the rare elemental mineral bismuth are particularly special. Chalcopyrite is another especially common associate. The carbonate mineral bismutite, Bi2(CO3)O2, is found as an alteration (oxidation) product of bismuthinite and often is found as pseudomorphic crystals after bismuthinite. A pseudomorph is an atom by atom replacement of one mineral by another without significant changes in the outward appearance of the crystals (pseudo="false" and morph="shape").

PHYSICAL CHARACTERISTICS:

  • Color is steel gray to off-white.
  • Luster is metallic.
  • Transparency crystals are opaque.
  • Crystal System is orthorhombic; 2/m 2/m 2/m
  • Crystal Habits include radiating acicular to prismatic columnar crystals. Sometimes in wonderful sprays that are similar to stibnite's crystal habits. Also granular and massive.
  • Cleavage is perfect in one lengthwise direction.
  • Fracture is uneven.
  • Hardness is 2
  • Specific Gravity is approximately 6.8 - 7.2 (well above average for metallic minerals)
  • Streak is gray.
  • Other Characteristics: Thin crystals are slightly flexible, but inelastic. There maybe a slight yellow or iridescent tarnish present. Crystals are usually striated and have some sectility.
  • Associated Minerals are numerous and include gold, bismuth, bismutite, quartz, andradite, chrysoberyl, almandine, barite, scheelite, pyrophyllite, kettnerite, wulfenite, gadolinite, wolframite, beryl, epidote, microcline, pyrite, chalcopyrite, arsenopyrite, covellite and several other sulfides.
  • Notable Occurrences are many and include Cornwall, England; Bolivia; Australia; Temiscaming County, Quebec, Canada; Guanajuato, Mexico; Brazil; Kingsgate, New South Wales, Australia and some excellent locations in Vogtland and Siegerland, Germany. From the United States there are several localities in Haddam, Connecticut; Beaver County, Utah; Kern County, California; several counties in Arizona and in Boulder County, Colorado.
  • Best Field Indicators are crystal habit, density, tarnish, softness and flexibility.
BISMUTHINITE specimens:
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BISMUTHINITE specimen bim-1
$ 30.00
Dims: 2.0 x 1.3 x 1.1" (5.1 x 3.3 x 2.9 cm)
Wt: 2.5 oz. (71 g)
7301 Decline, Victoria Mine, Elko County, Nevada, U.S.A.
Two foliated, prismatic Bismuthinite crystals are embedded in the quartz/chalcopyrite host of this hand specimen. They measure 1.2" (3.0 cm) and 0.6" (1.6 cm) in length respectively, and though the smaller one appears to be cleaved, the larger one is nearly intact. Both have a bright, silvery-white color and a bright metallic luster and have orthorhombic crystals that strongly resemble those of stibnite. The host material, made up of broken quartz and chalcopyrite, is attached to a gray, rust-stained shale.
no photo
bim-1 ($ 30.00)
7301 Decline, Victoria Mine, Elko County, Nevada, U.S.A.
BISMUTHINITE specimen bim-2
$ 25.00
Dims:0.9x0.8x0.6" (2.3x2.0x1.5 cm)
Wt: 0.3oz. (8g)
7301 dcl., Victoria Mine, Elko cty., Nevada
This specimen consists of a crystalline mass of silvery-white bismuthinite on a matrix of limestone. Accessory minerals are pyrite, chalcopyrite, and calcite. No terminations are present on the bismuthinite crystals; however, there are the vertical striations on the crystals.
no photo
bim-2 ($ 25.00)
7301 dcl., Victoria Mine, Elko cty., Nevada
BISMUTHINITE specimen bim-3
$ 73.00
Dims: 1.4x0.35x0.24" (3.6x0.9x0.6 cm)
Wt: 0.17 oz. (4.7g)
Tasna, Potosi, Bolivia
While it looks a lot like a crystal of stibnite, this is actually bismuthinite. The crystal appears to have been covered with a black crust of some sort, much of which has been removed to expose the bismuthinite. The mineral is a steel gray color, with a metallic luster. There are striations along the crystal. The exposed end is clearly a fracture, and the other end (covered by that black crust) is likely a natural crystal termination.
no photo
bim-3 ($ 73.00)
Tasna, Potosi, Bolivia
BISMUTHINITE specimen bim-4
$ 50.00
Dims: 1.45x1.06x0.81" (3.68x2.69x2.07cm)
Wt: 0.81 oz. (23.0g)
Tasna, Potosi, Bolivia
This specimen is mostly bismuthinite, as a loosely intergrown mass of crystals. Most of what is visible, however, is a dull and slightly greenish-gray coating of bismutite (Bismuth Carbonate Oxide) which is the common oxidation product of bismuthinite. The bismuthinite is exposed around the edges and provides the specimen with quite a bit of sparkle, as it has a good metallic luster. The crystals, while small, have good crystalline form with a variety of shapes.
no photo
bim-4 ($ 50.00)
Tasna, Potosi, Bolivia
BISMUTHINITE specimen bim-5
$ 30.00
Dims: 1.94x1.10x0.73" (4.92x2.80x1.86cm)
Wt: 1.12oz. (31.7g)
Victoria Mine, Dolly Varden District, Elko County, Nevada, USA
This specimen is a piece of quartz intergrown with bismuthinite crystals. Only a portion of the spray of bismuthinite has been exposed, but several points suggest that they are the tips of more crystals originating from the same spot. Some of the bismuthinite has a gold or irridescent tarnish, but some freshly exposed crystals are silver in color with a vitreous luster.
no photo
bim-5 ($ 30.00)
Victoria Mine, Dolly Varden District, Elko County, Nevada, USA
 

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