PROUSTITE
Specimen pro-4

Dims: 2.4 x 1.5 x 1.0" (6.1 x 3.8 x 2.5 cm)

Wt: 3.2 oz. (92 g)

Bulldog Mine, Creede, Mineral County, Colorado, U.S.A.

A small vein of semicrystalline Proustite extends into the metallic sulfide base of this specimen. This vein shows no definite crystal form, but any crystals would not exceed a few millimeters in diameter, so I cannot be sure. The Proustite has a deep red color and a pearly luster, and though it is transparent, it is rather hard to see against the dark gray base. The base rock itself is made up of a variety of sulfides that appear to include pyrite and/or chalcopyrite, tetrahedrite and/or galena, or a combination of any or all of these.

Dims: 0.3 x 0.2 x 0.2" (7 x 5 x 5 mm)

Wt: 0.3 oz. (9 g) w/ specimen box

Aue, Saxony, Germany

This Proustite specimen is very small, bordering on a micromount. It consists of a cluster of tiny Proustite crystals that appear to be in good condition (some obvious damage is present) and do not exceed 2 mm in length, width, or thickness. These crystals show a rather heavily warped hexagonal form due to intergrowth and have the deep red color and submetallic luster that is common for this specie. Another mineral also appears to be present, with a brighter metallic luster and a silvery-yellow color. According to the documentation, this other mineral is Sternbergite, a silver iron sulfide. There is no host rock present, and the piece is affixed inside a plastic thumbnail box.

Dims:1.6x0.9x0.9" (4.1x2.3x2.3 cm)

Wt: 0.8oz. (23g)

Song co., Henan prov., China

This specimen consists of dozens of minute crystals of proustite scattered throughout the matrix with flecks of native silver. This association is not surprising, considering that proustite is a silver arsenic sulfide. The crystals on this specimen are too small to study, even with a loupe. Proustite is named for the French chemist, J. Proust.

Dims:1.5x1.2x1.0" (3.8x3.0x2.5 cm)

Wt: 1.2oz. (34g)

Song co., Henan prov., China

Dozens of tiny crystals of proustite and flecks of native silver are interspersed throughout the matrix of the host material on this specimen. The crystals are far to small to study, even with a loupe.

Dims: 1.8x1.8x1.4" (4.5x4.5x3.5 cm)

Wt: 1.88 oz. (53.2g)

Imiter Deposit, Saghro Oriental, Anti-Atlas, Morocco

This specimen has some excellent proustite crystals resting on a host rock that appears to be a mixture of quartzite and several metal sulfides, almost certainly including tennantite and cobaltite. Under a loupe, many tiny areas are brightly irridescent, and a multitude of crystal shapes indicates that many different minerals are present. The best crystals are clearly the proustites, which are transparent, deep red, and have a vitreous luster. The largest of these is only a few millimeters long, but there are hundreds, scattered over (and through) the host rock.

Dims: 1.50x1.18x0.98" (3.8x3.0x2.5cm)

Wt: 0.96oz. (27.3g)

Imiter silver mine, Morocco

Maroon, lustrous crystals of proustite adorn the gray surface of this specimen. The proustite crystals are translucent (nearly transparent), prismatic crystals with shallow pyramidal terminations. There are crystals on nearly all sides of the specimen. One image shows the multitude of crystals on one face, while the other shows the largest crystals (on the opposite face).

Dims: 1.30x0.75x0.51" (3.3x1.9x1.3cm)

Wt: 0.52oz (14.7g)

Imiter silver mine, Morocco

This porous gray rock is host to hundreds of tiny proustite crystals - indeed, they are scattered on every surface and permiate the pores of the rock. The proustite crystals are a deep maroon color, nearly transparent, and have deep striations along the length of the prisms. In a few areas, the proustite has darkened towards black, but most of the crystals are fresh and red (very little darkening from exposure to light).