BISMUTHINITE
Specimen bim-4

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.

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.

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.

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.

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.