THE MINERAL CARNOTITE

  • Chemistry: K2(UO2)2(VO4)2- 1-3H2O , Hydrated Potassium Uranyl Vanadate.
  • Class: Phosphates
  • Group: Vanadium Oxysalt
  • Uses: An important ore of uranium and vanadium and as mineral specimens.
  • Specimens
Carnotite is a relatively uncommon mineral, yet common enough to be an important ore of uranium and vanadium. Uranium and vanadium are two extremely strategic metals. Carnotite is closely related to tyuyamunite, Ca(UO2)2(VO4)2- 5-8H2O. The chemistries are very similar with potassium replacing calcium and a different percentage of water, however the structures are slightly different as tyuyamunite is orthorhombic and carnotite is monoclinic. The two minerals are often found together and are essentially indistiguishable by ordinary methods. Meteoric oxygenated waters dissolve the uranium from primary uranium minerals and the uranium is later deposited in reducing enviroments more favorable to the formation of carnotite. Since many deposits in sandstones are associated with petrified trees and other fossils, it is reasonable to assume that the decaying material helped produce the required reducing enviroment. Carnotite is an uncommon and interesting uranium mineral that can coat host rocks with an attractive yellow powder. Remember, this is also a radioactive mineral and should be stored away from other minerals that are affected by radioactivity and human exposure should always be limited.

PHYSICAL CHARACTERISTICS:

  • Color is bright yellow.
  • Luster is pearly to dull or earthy.
  • Transparency: Crystals are translucent to opaque.
  • Crystal System is monoclinic; 2/m
  • Crystal Habits include crusts, earthy masses, foliated and granular aggregates.
  • Cleavage is perfect in one direction.
  • Fracture is uneven.
  • Hardness is 2.
  • Specific Gravity is approximately 4 - 5 (heavy for translucent minerals), higher gravity with lower water content.
  • Streak is yellow.
  • Associated Minerals include other uranium and vanadium minerals in sandstones and limestones.
  • Other Characteristics: Radioactive and not fluorescent.
  • Notable Occurrences include many locations in Wyoming, Colorado, Arizona, Utah, Grants, New Mexico and Mauch Chunk, Carbon Co, Pennsylvania, USA; Shaba, Zaire; Morocco; Radium Hill, Australia and Kazakhstan.
  • Best Field Indicators are bright yellow color, density, habit, lack of any fluorescence, radioactivity and associations.
CARNOTITE specimens:
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CARNOTITE specimen car-1
$ 105.00
Dims: 3.3" x 2.4" x 1.0"(8.4 X 6.1 X 2.5 cm)
Wt: 3.59 oz.(101.9 g)
Hidden Splendor Mine, Emery County, Utah, U.S.A.
An impressive amount of Carnotite rests on the sandstone host of this specimen; it looks like a yellow powder that has been sprinkled on the host. A few areas have enough of a concentration of this powder to make a crust. It is a bright yellow in color and has no luster to speak of. There are a few small crushed clusters of a colorless crystalline substance that I believe is selenite. A few of these are yellow due to included Carnotite. This specimen is a classic example of this mineral, and was collected sometime in the 1950's.
no photo
car-1 ($105.00)
Hidden Splendor Mine, Emery County, Utah, U.S.A.
CARNOTITE specimen car-2
$ 70.00
Dims: 2.3" x 1.5" x 0.9" (5.8 x 3.8 x 2.3 cm)
Wt: 1.83 oz. (52.1 g)
Moab, Utah, U.S.A.
A few concentrated patches of powdery Carnotite rest on the gray-brown host rock of this specimen. The Carnotite simply looks like a very fine, deep-yellow dust that has been spread generously on certain parts of the host rock. Its color shows a faint hint of orange, and has a dull luster. I think that it is opaque, though it is impossible to be certain. The host rock contains a few rusty patches and seems to show some subtle veining on one side, where the Carnotite is not very concentrated.
no photo
car-2 ($ 70.00)
Moab, Utah, U.S.A.
CARNOTITE specimen car-3
$ 28.00
Dims: 3.7" x 2.6" x 0.7" (9.4 x 6.6 x 1.8 cm)
Wt: 2.74 oz. (77.7 g)
Anderson Mine, Yavapai County, Arizona, U.S.A.
This hand specimen consists of a layer of yellow Carnotite that is sandwiched in between layers of a soft shale. Though it has a bright yellow coloration and appears to be pure, I believe that the layer consists merely of a layer of shale that has been partly saturated with the powdery Carnotite. One can see that though the layer passes completely through the rock, it is patchy and not visible in some areas along the specimen's edge. However, there is still a substantial amount present in this specimen. As with most Carnotite, this material is powdery and lacks any visible crytal form. It has the standard bright yellow coloration and a dull luster.
no photo
car-3 ($ 28.00)
Anderson Mine, Yavapai County, Arizona, U.S.A.
CARNOTITE specimen car-4
$ 28.00
Dims: 3.1" x 2.9" x 0.7" (7.9 x 7.3 x 1.8 cm)
Wt: 3.51 oz. (99.8 g)
Anderson Mine, Yavapai County, Arizona, U.S.A.
This hand specimen consists of another Carnotite-rich layer in a pale brown shale host rock. The Carnotite takes on the standard form of a bright yellow powder that permeates a layer of shale. It shows no crystal form. Actually, it would appear that there are 2 layers of this material in the host rock. One of the layers consists merely of the edge of the layer that is in this specimen, while the other layer extends almost completely through the specimen, ending where the other begins.
no photo
car-4 ($ 28.00)
Anderson Mine, Yavapai County, Arizona, U.S.A.
CARNOTITE specimen car-5
$ 45.00
Dims: 4.4 x 2.3 x 0.8" (11.2 x 5.8 x 2.0 cm)
Wt: 3.10 oz. (87.9 g)
near Goulding's Well, Navajo County, Arizona, U.S.A.
Several tiny Carnotite "nodules" rest on the gray sedimentary host rock of this specimen. These "nodules" do not exceed 1 mm in diameter, and thus are very difficult to study without high magnification. Each appears to consist of a tight cluster of radiating monoclinic blades that have an almost pseudohexagonal appearance. All have a yellow color with tinges ranging from green to orange, and are too small for me to effectively define their luster or clarity. They rest on a rusty face of what appears to be a slab of shale or a finely-grained sandstone host rock.
no photo
car-5 ($ 45.00)
near Goulding's Well, Navajo County, Arizona, U.S.A.
CARNOTITE specimen car-6
$ 48.00
Dims: 2.8 x 2.8 x 0.7" (7.1 x 7.1 x 1.8 cm)
Wt: 3.51 oz. (99.6 g)
near Goulding's Well, Navajo County, Arizona, U.S.A.
At least 20 tiny Carnotite nodules rest on the rusty, chalky host rock of this specimen. According to the enclosed documentation, these were "crystals". I did not believe this until I examined the specimen with a 10-power loupe. The nodules are actually clusters of intergrown, radiating Carnotite blades that do not exceed 1 or 2 mm in diameter. Some of the clusters are broken, but most are undamaged. Their monoclinic bladed form is moderately good, as most of the crystals appear to be rounded. However, higher magnification may reveal examples of better crystal form. Most have dull yellow coloration that is slightly rust-stained, but the damaged clusters are denoted by a brighter yellow color. They are generally dull in luster and are only dimly translucent even at their small size. The host rock appears to consist of a finely-grained sandstone or rough shale, and shows heavy rust-staining.
no photo
car-6 ($ 48.00)
near Goulding's Well, Navajo County, Arizona, U.S.A.
CARNOTITE specimen car-7
$ 60.00
Dims: 3.2 x 1.9 x 1.6" (8.1 x 4.8 x 4.0 cm)
Wt: 5.9 oz. (167 g)
Moab, San Juan County, Utah, U.S.A.
This rather interesting cabinet piece consists of a base of petrified wood which is almost completely dusted with powdery Carnotite. Being a powder, the Carnotite shows no crystal form and no appreciable damage. It has the standard bright yellow color and dull luster, and is, of course, radioactive. The slightly rounded petrified wood base shows noticeable rust-staining, and is free from any form of host rock.
no photo
car-7 ($ 60.00)
Moab, San Juan County, Utah, U.S.A.
CARNOTITE specimen car-8
$ 25.00
Dims: 2.6 x 2.3 x 2.2" (6.5 x 5.8 x 5.5 cm)
Wt: 7.1 oz. (201 g)
Thompson Canyon, Green River, Utah, U.S.A.
This cabinet piece consists of a conglomerate base rock that is partly coated with a thin Carnotite crust. The crust shows no evidence of crystal form whatsoever and has a deep yellow color and a matte luster. There are patches of a paler yellow, crumbly material in the base rock- I cannot be sure if this is more carnotite or perhaps a different, related uranium mineral.
no photo
car-8 ($ 25.00)
Thompson Canyon, Green River, Utah, U.S.A.
CARNOTITE specimen car-9
$ 50.00
Dims:2.2x2.1x1.6" (5.6x5.3x4.1 cm)
Wt: 3.8oz. (107g)
Firefly-Pigmay Mine, San Juan cty., Utah
The top surface of this sandstone matrix is coated with a thin crust of yellow carnotite. This mineral is in the form of tiny nodules and flakes. There is no damage to this specimen.
no photo
car-9 ($ 50.00)
Firefly-Pigmay Mine, San Juan cty., Utah
CARNOTITE specimen car-10
$ 75.00
Dims:1.7x1.2x0.9" (4.3x3.0x2.3 cm)
Wt: 1.4oz. (39g)
Utah
The matrix of this specimen bears a rich crust of carnotite, as well as some minor pyrite. The carnotite is mustard-yellow in color,and is massive in form. There is no damage to this specimen.
no photo
car-10 ($ 75.00)
Utah
CARNOTITE specimen car-11
$ 30.00
Dims: 1.40x1.21x0.33" (3.54x3.08x0.84cm)
Wt: 0.42oz (11.8g)
Anderson Mine, Yavapai County, Arizona, USA
The off-white host rock of this specimen has crusts of two minerals. The bright yellow crust is carnotite, which is relatively thick on the edges but present to a lessor extent on the faces as well. Accompanying the carnotite is a thin, greenish-yellow crust of tyuyamunite. Under a UV lamp, the carnotite does not fluoresce, while the tyuyamunite fluoresces a very weak yellow-green under short wave illumination.
no photo
car-11 ($ 30.00)
Anderson Mine, Yavapai County, Arizona, USA
CARNOTITE specimen car-12
$ 25.00
dims mm=37.64x20.51x16.58
wt g=17.8
Oljeto Mine, San Juan County, Utah, USA
The brilliant yellow crust on one side of this specimen (and in a few small patches on the reverse) is a typical example of carnotite. There is no indication of crystals, even when viewed with a loupe.
no photo
car-12 ($ 25.00)
Oljeto Mine, San Juan County, Utah, USA
 

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