Carnotite
From Wikipedia, the free encyclopedia
| Carnotite | |
|---|---|
 |
|
| General | |
| Category | Mineral |
| Chemical formula | K2(UO2)2(VO4)2·3H2O |
| Identification | |
| Color | Yellow, Golden yellow, Greenish yellow |
| Crystal habit | crusts, earthy masses, foliated and granular aggregates. |
| Crystal system | Monoclinic; 2/m |
| Cleavage | perfect: one direction |
| Fracture | uneven |
| Mohs Scale hardness | 2 |
| Luster | pearly to dull or earthy |
| Refractive index | nα=1.750 - 1.780, nβ=1.901 - 2.060, nγ=1.920 - 2.080 |
| Streak | yellow |
| Specific gravity | 4 - 5 |
| Other Characteristics |  Radioactive,not fluorescent |
Carnotite is a potassium uranium vanadate mineral with chemical formula: K2(UO2)2(VO4)2·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.
Carnotite is a bright to greenish yellow mineral that occurs typically as crusts and flakes in sandstones. Amounts as low as one percent will color the sandstone a bright yellow. The high uranium content makes carnotite an important uranium ore and also radioactive. It is a secondary vanadium and uranium mineral usually found in sedimentary rocks in arid climates. It is an important ore of uranium in the Colorado Plateau region of the United States where it occurs as disseminations in sandstone and concentrations around petrified logs. Occurs in the states of Wyoming; Colorado; Arizona; Utah; It also occurs incidentally in Grants, New Mexico and Carbon County, Pennsylvania. It is also reported in Zaire; Morocco; Radium Hill, Australia; and Kazakhstan.
The mineral was first described in 1899 by French scientists M. M. C. Freidel and E. Cumenge, who identified it in specimens from Roc Creek in Montrose County, Colorado, United States.[1] It is named for Marie Adolphe Carnot (1839 - 1920), French mining engineer and chemist.
Several related mineral species exist, including: margaritasite ((Cs,K,H3O)2(UO2)(VO4)2·H2O) and tyuyamunite, (Ca(UO2)2(VO4)2·5-8H2O).
[edit] See also
[edit] References
- ^ Robert J. Wright and Donald L. Everhart (1960) Uranium, in Mineral Resources of Colorado First Sequel, State of Colorado Mineral Resources Board, p.330-331.
- Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., John Wiley and Sons, New York ISBN 0-471-80580-7
- Webmineral
- Univ. of Virginia
- Mineral Galleries
- Mindat.org
