CYLINDRITE
Specimen cyl-8

Dims: 2.6 x 1.6 x 1.2" (6.6 x 4.1 x 3.0 cm)

Wt: 2.73 oz. (77.4 g)

Poopo, Bolivia

This large thumbnail specimen consists of countless intergrown Cylindrite crystals. These crystals are in moderately good condition and achieve lengths of up to 1.1" (2.8 cm). All have the standard triclinic needle-like form that appears to have a perfectly round cross-section- each crystal basically looks like a dark, thick needle. They have the standard dark gray color and dull metallic luster of their species and are accompanied by bits of another sulfide mineral that has a rather dull golden color and a dull metallic luster- it might be pyrite or one of its close relatives. There is a small, dirty crust of crystalline quartz at one end of the piece, but no actual host rock is present.

Dims: 1.5 x 0.5 x 0.3" (3.8 x 1.3 x 0.8 cm)

Wt: 6.8 g

Poopo, Bolivia

This small thumbnail specimen is made up almost entirely of intersecting Cylindrite crystals. These crystals are in moderately good condition, as much damage is evident, and reach lengths of up to 1.3" (3.3 cm) or more. All have the standard trigonal prismatic form that features the round, tapering cylindrical shape that is a hallmark of this mineral, and the dark silvery-gray color and dull metallic luster that are often standar for metallic sulfides. There is no host rock present.

Dims: 4.9 x 2.3 x 1.9" (12.4 x 5.8 x 4.8 cm)

Wt: 14.7 oz. (417 g)

near Llallagua, Potosi Department, Bolivia

A large spray of Cylindrite spikes permeates the gray metallic host rock of this cabinet specimen. It is likely that many of these crystals exceed 2" (5 cm) in length, and though many of the exposed crystals are damaged or incomplete, those that extend into the host are in good condition. The crystals have the classic cylindrical shape that is the hallmark and namesake of the specie, and all have a dark silvery-gray color and a dull metallic luster- each strongly resembles the lead of a pencil. I cannot define the host rock, but it appears to contain a substantial amount of calcite.

Dims: 2.6 x 1.6 x 1.0" (6.6 x 4.2 x 2.6 cm)

Wt: 4.3 oz. (121 g)

near Llallagua, Potosi Department, Bolivia

This hand specimen consists of many heavily intergrown Cylindrite sprays. Each of these sprays is made up of dozens of tightly packed Cylindrite crystals, most of which are broken or damaged to some degree, that reach lengths of 1.3" (3.3 cm). These crystals have good form and the classic long, thin cylindrical shape whence comes their name. Their color is a moderately dark silvery-gray and their luster is metallic and rather dull. A small amount of a nondescript, dull-gray host rock is present.

Dims: 2.3 x 1.8 x 1.1" (5.9 x 4.5 x 2.7 cm)

Wt: 3.4 oz. (96 g)

near Llallagua, Potosi Department, Bolivia

Several Cylindrite sprays are embedded in the metallic host rock of this hand specimen. Each spray is made up of many radiating Cylindrite crystals, some of which are damaged or broken due to their exposure- they reach lengths of just over 1" (2.5 cm). All have excellent cylindrical shape (hence their name) and the standard dark silvery-gray color and dull metallic luster. I cannot define the host rock, but it is definitely metallic in nature.

Dims: 2.0 x 0.9 x 0.7" (5.0 x 2.4 x 1.7 cm)

Wt: 24 g

near Llallagua, Potosi Department, Bolivia

Scores of Cylindrite crystals are partly intergrown to form this hand specimen. The crystals are in fair condition at best, as most of them are broken and incomplete, and do not tend to exceed 1" (2.5 cm) in length. All have the tapering, cylindrical form that is classic for this mineral, along with the standard dark gray color and dull metallic luster. There does not appear to be any other material present.

Dims: 1.4 x 1.4 x 1.0" (3.6 x 3.5 x 2.5 cm)

Wt: 1.9 oz. (55 g)

near Llallagua, Potosi Department, Bolivia

This lovely hand specimen is made up almost entirely of intergrown Cylindrite needles. These needles reach nearly 1.5" (3.8 cm) in length and are generally in good condition - though many are noticeably damaged, several have complete terminations, including one particularly exposed crystal. All have a thin, cylindrical habit and are considered trigonal in form. Their gray color and dull metallic luster are standard for the specie, and all are, of course, opaque.

Dims: 2.8x1.4x2.0" (7.1x3.5x5.1 cm)

Wt: 5.7 oz. (162g)

Colquechaca, Potosi, Bolivia

This hand specimen is mostly cylindrite by weight, and features some cylinders that are up to 3mm in diameter. Also, some of the crystals reveal their true form, as rolled up sheets of the mineral that only appear cylindrical. The remainder of the specimen is a nearly massive reddish-brown mineral, likely cassiterite.

Dims: 2.8x2.2x2.2" (7.0x5.6x5.6cm)

Wt: 12.2 oz. (344g)

Colquechaca, Potosi, Bolivia

This cylindrite specimen has some of the largest (diameter) cylindrite crystals I have ever seen. Many specimens have much longer crystals, but I don't remember any as "fat" as these. A number of the crystals exceed 2mm in diameter, with one approaching 3mm. There are many somewhat radial clusters of crystals, although for the most part, the specimen is composed of masses of intergrown cylinders. There are other minerals present, notably including many small transparent quartz crystals, patches of what appears to be sphalerite, and some interesting black "roses" which may be hematite.