The Mineral TORBERNITE
- Chemistry: Cu(UO2)2(PO4)2-10H2O , Hydrated Copper Uranyl Phosphate
- Class: Phosphates
- Group: Autunite/Torbernite
- Uses: a minor ore of uranium and mineral specimens
Specimens
The structure of torbernite is composed of phosphate tetrahedrons linked to uranium-oxygen groups that form distorted octahedrons. The phosphates and uranium groups lie in sheets that are weakly held together by water molecules. This structure produces the tabular habit, the one perfect direction of cleavage and the relative softness.
Torbernite can lose water and convert to a different mineral called meta-torbernite of the meta-autunite/meta-torbernite group of minerals. The change to meta-torbernite will often produce a pseudomorph. A pseudomorph is generally an atom by atom replacement of one mineral's chemistry to form another mineral. The process leaves the crystal shape of the lost mineral intact. Pseudomorph means false (psuedo) shape (morph). In this case, the conversion is not so dramatic since it involves only the loss of a few water molecules and therefore a good pseudomorph is likely. The conversion is irreversible and ongoing and all collection specimens of a certain age are almost certainly partially to totally converted.
The presence of torbernite crystal has been used by prospectors as an indicator of profitable uranium ore in the area. Fine torbernite specimens should be stored in a closed container to avoid water loss. Remember, this is a radioactive mineral and should be stored away from other minerals that are affected by radioactivity and human exposure should be limited.
PHYSICAL CHARACTERISTICS:
- Colors are various shades of dark to light green.
- Luster is vitreous to pearly on the main pinacoid.
- Transparency crystals can be transparent but more commonly are translucent to opaque.
- Crystal System is tetragonal; 4/m 2/m 2/m
- Crystal Habits include tabular square crystals dominated by two pinacoid faces. Crystals can look cubic, but the pearly luster only on the pinacoid faces gives the true symmetry away. Crystals can form in parallel growths giving a "stacked book" kind of look. Also as crusts, micaceous, foliated and scaly aggregates.
- Cleavage is perfect in one direction.
- Fracture is uneven.
- Hardness is 2 - 2.5
- Specific Gravity is approximately 3.2+ (slightly above average for translucent minerals)
- Streak is a pale green.
- Associated Minerals are autunite,
uranophane , uranocircite, meta-torbernite, uraninite and other uranium minerals. - Other Characteristics: radioactive and cleavage sheets are not bendable but are in fact brittle.
- Notable Occurences include Cornwall, England; Mitchell Co., North Carolina and Utah, USA; Shaba, Zaire; Germany and France.
- Best Field Indicators are color, crystal habit, non-fluorescence, radioactivity, associations and brittle cleavage sheets.
 Amethyst Galleries' Mineral Gallery MINERALS |
TORBERNITE specimen tor-1
$ 60.00
$ 60.00
Dims: 1.8" x 1.8" x 1.6"(4.6 x 4.6 x 4.1)
Wt: 3.14 oz.(89.2 g)
Musonoie Mine, Kolwezi, Zaire
Wedged into a crevice in the host rock of this specimen lies a crust made up of hundreds of tightly-packed Torbernite crystals. They have a deep green color, pearly luster, and are transparent, likely due to the thinness of the thin, square, tabular crystal form in which they occur. None of the tablets are very large, but there are a few edges of crystals that measure up to 0.2"(5 mm) in length. There is a considerable amount of damage to the cluster, but most of the crystals are intact. The host is quite grainy, and looks like some type of sandstone. There are traces of the green mineral all over the specimen, and it probably pervades the entire specimen.
tor-1 ($ 60.00)
Musonoie Mine, Kolwezi, Zaire
TORBERNITE specimen tor-2
$ 75.00
$ 75.00
Dims: 2.7" x 2.0" x 1.9"(6.9 x 5.1 x 4.8)
Wt: 5.22 oz.(148.1 g)
Musonoie Mine, Kolwezi, Zaire
It is difficult to determine what the host rock is on this specimen- I would guess a hard shale or fine-grained sandstone. I do know, however, that at least 30% of its surface area is covered with a crust of tightly-packed Torbernite crystals. These crystals occur as thin, square-shaped tabular blades and are tightly intergrown. Their color is a uniform dark green, they have a pearly luster, and individual crystals are transparent. There is heavy damage- over 50% of the blades are broken. There is a lot of material on this crust, and veins of Torbernite, and possibly some malachite, permeate the host rock. I am guessing that the copper minerals in this specimen make up over half its weight.
tor-2 ($ 75.00)
Musonoie Mine, Kolwezi, Zaire
TORBERNITE specimen tor-3
$ 65.00
$ 65.00
Dims: 2.7" x 1.6" x 1.5" (6.9 x 4.1 x 3.8)
Wt: 4.15 oz. (117.9 g)
Musonoie Mine, Shaba Province, Zaire
Many small, tabular blades of Torbernite line the crevices of the broken, chalky host rock of this specimen. These bladed crystals are generally in good condition, though damage is obvious in many places. They have sharp edges and smooth faces that show a pearly luster, and their green color is slightly different than that of the accompanying malachite. They are transparent and relatively clear. The malachite that is present on the specimen is amorphous in some places and shows a botryoidal form in others. It has a dull luster, and is, of course, opaque. The malachite formed some time after the Torbernite, as it lined the same crevices, partially enveloping some of the bladed crystals (see the close-up image).
tor-3 ($ 65.00)
Musonoie Mine, Shaba Province, Zaire
TORBERNITE specimen tor-5
$ 100.00
$ 100.00
Dims: 2.9" x 2.0" x 1.6" (7.4 x 5.1 x 4.1)
Wt: 4.74 oz. (134.5 g)
Musonoie Mine, Shaba Province, Zaire
This hand specimen consists of several clusters of square, tabular Torbernite crystals that are resting on a weathered, pale brown host rock that is permeated with veins of massive malachite. Though none of these crystals exceeds 0.1" (3 mm) in any dimension, they are in excellent condition, showing almost no damage, and have excellent tetragonal tabular form. Their color is the standard grass-green for this mineral, their luster is pearly, and all are dimly transparent. As with most copper-based minerals, these crystals will not glow under UV light, even with their uranium content. There are a few small hollows scattered on the specimen that contain a few more Torbernite blades, and several small areas that show shards of broken crystals. The malachite that pervades the host rock is massive and formless, showing a dull, waxy luster.
tor-5 ($100.00)
Musonoie Mine, Shaba Province, Zaire
TORBERNITE specimen tor-6
$ 100.00
$ 100.00
Dims: 2.7" x 2.1" x 1.4" (6.9 x 5.4 x 3.6)
Wt: 3.55 oz. (100.6 g)
Musonoie Mine, Shaba Province, Zaire
This lovely specimen consists of several clusters of small tetragonal tabular Torbernite crystals that rest on a brown host rock. These crystals do not exceed 0.1" (3 mm) in diameter, and though several of them show obvious damage, the majority are intact and in very good condition. All have the deep grass-green coloration and pearly luster that one expects from this mineral, and individually, the tablets are transparent and quite clear, though their intergrowth provides much interference. The brown host rock is formless and nondescript, but contains tiny pockets which are lined with more of these green crystals.
tor-6 ($100.00)
Musonoie Mine, Shaba Province, Zaire
TORBERNITE specimen tor-7
$ 120.00
$ 120.00
Dims: 3.6" x 2.7" x 1.5" (9.1 x 6.9 x 3.8 cm)
Wt: 5.0 oz. (140.5 g)
Musonoie Mine, Shaba Province, Zaire
Though there are areas of noticeable damage on this hand speicmen, most of the crust of intergrown Torbernite blades that rest on it are in excellent condition. The bladed crystals have a tetragonal tabular form that ranges from square-shaped to round, flat platelets, and possess a pearly luster. They do not exceed 0.3" (8 mm) in diameter. All have the standard forest-green coloration that is characteristic of this mineral and are dimly translucent to dimly transparent, depending on their compactness and intergrowth. They rest on what appears to be a quartzite base rock that is covered by a thin layer of a crumbly brown- and black-colored substance that is likely a product of another mineral's decay.
tor-7 ($120.00)
Musonoie Mine, Shaba Province, Zaire
TORBERNITE specimen tor-8
$ 30.00
$ 30.00
Dims: 2.0 x 1.3 x 1.1" (5.1 x 3.3 x 2.8 cm)
Wt: 1.05 oz. (29.7 g)
Musonoie Extension, Shaba Province, Zaire
The pale brown host rock of this thumbnail specimen is sparsely coated with dozens of small Torbernite blades. Many of these blades are broken or incomplete, but there are several that are still in good condition. They do not tend to exceed 0.1" (3 mm) in either length or width, and are much thinner than 1 mm. All have a moderate grass-green coloration and are transparent and rather clear due to their thinnness. On one side of the specimen, several crystals rest inside a depression and are at least partly coated with what appears to be malachite. The malachite has a dull silky luster compared to the almost vitreous luster of the Torbernite, and has a slightly darker green color.
tor-8 ($ 30.00)
Musonoie Extension, Shaba Province, Zaire
TORBERNITE specimen tor-9
$ 55.00
$ 55.00
Dims: 2.1 x 1.8 x 1.5" (5.3 x 4.6 x 3.8 cm)
Wt: 2.12 oz. (60.1 g)
Musonoie Extension, Shaba Province, Zaire
Hundreds of small, round Torbernite blades make up the crust that partly coats the gray-black host rock of this specimen. These blades do not exceed 0.2" (5 mm) in diameter or 2 mm in thickness, and are generally in good condition, though a few of the most exposed ones are damaged. Their tetragonal tabular form is fair, as most of the blades are rounded due to intergrowth. They possess the standard grass-green color and pearly luster of their species, and are moderately to dimly translucent when not in clusters. The host rock appears to be made of a gray quartzite that is suffused with a darker, almost black mineral that I cannot identify- it might be a decomposition product of another mineral.
tor-9 ($ 55.00)
Musonoie Extension, Shaba Province, Zaire
TORBERNITE specimen tor-10
$ 100.00
$ 100.00
Dims: 2.1 x 1.9 x 1.3" (5.3 x 4.8 x 3.3 cm)
Wt: 2.83 oz. (80.2 g)
Musonoie Mine, Shaba Province, Zaire
Scores of slightly- to heavily-intergrown Torbernite crystals are scattered about the pale brown host rock of this specimen. These crystals do not exceed 0.1" (3-4 mm) along any axis and are generally in good condition, though there are several areas of visible damage. All appear to have good tetragonal tabular form, with sharp edges and clean faces that possess the standard pearly luster. All have a moderately dark, forest-green coloration and are transparent as individuals, but nearly opaque when tightly intergrown. The pale brown host rock appears to be made of a calcareous shale and has several black patches where other minerals may have decomposed from the radiation.
tor-10 ($100.00)
Musonoie Mine, Shaba Province, Zaire
TORBERNITE specimen tor-11
$ 130.00
$ 130.00
Dims: 6.0 x 3.2 x 3.0" (15.2 x 8.1 x 7.6 cm)
Wt: 2 lbs., 13.1 oz. (1.279 kg)
Musonoie Mine, Kolwezi, Shaba Province, Zaire
This cabinet specimen consists of a pale brown rock that is partly covered with hundreds of heavily-intergrown Torbernite crystals on one face. These crystals are generally in poor condition, as nearly all of them are broken and incomplete, and some are noticeably crushed. Even so, there is a lot of Torbernite on the piece, and those crystals that are intact show excellent tetragonal tabular form. All have the standard deep, grass-green coloration and pearly luster, and all are transparent and dimly-to-moderately clear, depending on their intergrowth.
tor-11 ($130.00)
Musonoie Mine, Kolwezi, Shaba Province, Zaire
TORBERNITE specimen tor-12
$ 70.00
$ 70.00
Dims: 3.9 x 2.0 x 1.6" (9.9 x 5.1 x 4.1 cm)
Wt: 5.15 oz. (146.1 g)
Musonoie extension, Shaba Province, Zaire
The brown-gray host rock of this hand specimen is partly coated with a crust of intergrown Torbernite blades. These blades generally do not exceed 0.1" (3 mm) and are in moderately good condition, showing considerable damage where they are well exposed. All have excellent tetragonal tabular form, a grass-green color and a pearly luster. They are transparent and dimly to moderately clear where applicable.
tor-12 ($ 70.00)
Musonoie extension, Shaba Province, Zaire
TORBERNITE specimen tor-13
$ 25.00
$ 25.00
Dims:1.5x1.5x0.7" (3.8x3.8x1.8 cm)
Wt: 1.0oz. (27g)
San Antonio de la Huerta, Sonora, Mexico
This specimen consists of a weathered piece of matrix hosting severel fragments of torbernite crystals. Upon examination with a loupe, several partial crystals of torbernite are visible, but I saw no terminated edges to these fragments. The top of this specimen has weathered down to a layer of limonite.
tor-13 ($ 25.00)
San Antonio de la Huerta, Sonora, Mexico
TORBERNITE specimen tor-14
$ 45.00
$ 45.00
Dims:1.5x1.4x1.1" (3.8x3.6x2.8 cm)
Wt: 1.3oz. (36g)w/base
Shinkolobwe, Zaire
A cavity in the matrix of this specimen is host to many tabular crystals of torbernite to 0.1" (0.3cm) on edge. The crystal form displayed, and the general appearance of this specimen are excellent. There is no damage to this piece. It is firmly glued to a clear acrylic base.
tor-14 ($ 45.00)
Shinkolobwe, Zaire
TORBERNITE specimen tor-15
$ 49.00
$ 49.00
Dims: 1.57x1.10x1.02" (4.0x2.8x2.6cm)
Wt: 1.30oz (36.8g)
Musonoi, Zaire
One surface of the host rock is covered with forest green torbornite crystals. They exist as heavily intergrown square blades, and most of them are translucent with a dull luster, but the larger crystals (of which there are at least 100) are transparent with a vitreous luster, and have excellent crystal form and terminations. The largest crystals (perhaps 4mm in length) appear to have multiple layers, and the upper layers are incomplete, giving an appealing surface texture due to the stepped crystal growth.
tor-15 ($ 49.00)
Musonoi, Zaire
TORBERNITE specimen tor-16
$ 45.00
$ 45.00
Dims: 2.40x1.52x1.09" (6.10x3.86x2.77cm)
Wt: 1.72oz (48.6g)
Shinkolobwe, Zaire
The torbernite crystals on this specimen are deep green, translucent, and the individual crystals have a vitreous luster. Some crystals show hints of transparency. They are organized in books of square flat crystals, although the hundreds of "books" have random orientations and have an open layout.
tor-16 ($ 45.00)
Shinkolobwe, Zaire