COBALTITE
Specimen cob-4

Dims: 2.4" x 1.7" x 1.5"(6.1 x 4.3 x 3.8 cm)

Wt: 4.29 oz.(121.7 g)

Riddarhyttan, Vastmanland, Sweden

Many Cobaltite crystals are embedded in the pyrrhotite matrix of this specimen. Though the Cobaltite's silvery-white color contrasts with the deep brown-gold of the matrix, the crystals are still difficult to see, as most of them are extremely small and there are many platelets of what appears to be biotite, whose pearly luster resembles the dull metallic luster of the tiny Cobaltites. One crystal, however, is very easy to see due to its size; it is much larger than any other visible crystal, with visible dimensions of 0.4 x 0.3"(1.0 x 0.8 cm). From the faces that can be seen, I am pretty certain that it possesses the pyritohedral crystal form that is quite common for this mineral. It is undamaged, though it is rough in form and marred by small, yellow metallic crystals embedded in it(likely pyrrhotite). Its Swedish locality is well-known, and it was collected there sometime between 1950 and 1960.

Dims: 1.8" x 1.8" x 1.3" (4.6 x 4.6 x 3.3 cm)

Wt: 4.09 oz. (115.9 g)

Pellegruvan, Riddarhyttan, Vastmanland, Sweden

This small hand specimen consists of at least 10 Cobaltite crystals that are partially embedded in a brown, muscovite-laden matrix rock. While none of these crystals show any human-induced damage, their forms are rather rounded for the most part, and several of the crystals are incomplete due either to growing conditions or to intergrowth with each other. The largest of these crystals has a diameter of 0.2" (5 mm), and though it is incomplete, it shows the best pyrithohedral form of the group. All have a bright, silvery color and a metallic luster and are, of course, opaque.

Dims: 1.1" x 1.0" x 0.6" (2.8 x 2.5 x 1.5 cm)

Wt: 25.4 g

Hakansboda, Sweden

This thumbnail specimen consists of a metallic host rock in which rest several Cobaltite crystals. These crystals show moderately good pyritohedral form, though they are warped and the largest one is slightly damaged. It measures 0.4" (1.0 cm) in diameter, whereas the other crystals average 0.1" (3 mm) in diameter. It would seem, however, that most of the matrix that contains these crystals is made up of either more Cobaltite or a similar sulfide mineral, as it also has a bright silvery coloration and a metallic luster. There are also a few tiny patches of a metallic mineral that has a deep golden coloration- I do not know what it is, though it is likely related to the Cobaltite.

Dims: 1.2 x 1.1 x 0.7" (3.0 x 2.8 x 1.8 cm)

Wt: 1.2 oz. (34.6 g)

Pellegruevan, Riddarhyttan, Vaestmanland, Sweden

This small specimen consists of several pyritohedral Cobaltite crystals that are embedded in a matrix that itself appears to be made of a metallic mineral. One crystal in particular is exposed, and it appears to be the only one that shows any damage, which is minor. It measures 0.2" (5 mm) in diameter and shows excellent form, with well-defined edges and clean faces that possess a bright metallic luster. It has the standard silvery-white color of Cobaltite, and somehow I get the feeling that the matrix itself is made up either of more, massive Cobaltite, or a closely-related metallic sulfide.

Dims: 1.7 x 1.6 x 1.4" (4.3 x 4.1 x 3.6 cm)

Wt: 3.50 oz. (99.4 g)

Elizabeth Lake, Espanola, Ontario, Canada

Several warped Cobaltite cubes are embedded in what appears to be a feldspar matrix in this specimen (actually, the matrix reminds me of labradorite, but lacks the color). Approximately half of them are damaged and possibly incomplete, though most are almost completely obscured by the matrix. Only one has good cubic form, with well-defined edges and clean faces, and it has visible dimensions of 0.2 x 0.2 x 0.1" (0.5 x 0.5 x 0.4 cm). All have the silvery-white color and metallic luster that are standard for this mineral, but their luster is slightly dull and many show a colorful iridescence that denotes a slight oxide or decomposition coating. There are likely more crystals trapped in this matrix, and one could easily expose more of those

Dims: 1.2 x 1.0 x 0.7" (3.0 x 2.5 x 1.7 cm)

Wt: 17 g w/ base

Hakansboda Mine, Vastmanland, Sweden

This thumbnail specimen consists of a single Cobaltite crystal that is partly embedded in a metallic sulfide base. This crystal measures about 0.2" (5 mm) in diameter and is in good condition, showing little fresh damage. Its pyritohedral form is somewhat warped but still reasonably good, and it has the standard bright silvery-gray color and bright metallic luster of its specie. The piece is hot-glued onto a flat, acrylic base.

Dims: 0.65x0.62x0.56" (1.65x1.56x1.42cm)

Wt: 0.17oz (4.7g)

Elizabeth Lake, Espanola, Ontario, Canada

This specimen displays several intergrown cubic crystals of cobaltite in a matrix that appears to be a plagioclase feldspar. The largest of the cobaltite crystals is retangular rather than a cube, and is missing one corner but it appears to be a growth pattern showing striations, and not damage. The other crystals are progressively smaller cubes. All have a bright silvery metallic appearance, somewhat reminiscent of galena. There is a network of fine cracks in the largest crystal, which is missing a tiny bit of one corner (damage). The next smaller crystal is missing quite a bit of one corner, exposing the uneven fracture of cobaltite.