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Carnotite

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Marie-Adolphe Carnot
Formula:
K2(UO2)2(VO4)2 · 3H2O
System:
Monoclinic
Colour:
Bright yellow, yellow, ...
Lustre:
Sub-Vitreous, Resinous, Waxy, Silky, Dull, Earthy
Hardness:
2
Member of:
Name:
Named in 1899 by Charles Friedel and Édouard Cumenge in honor of Marie-Adolphe Carnot [January 27, 1839 Paris, France - June 20, 1920], French mining engineer and chemist, professor at École des Mines and, later Chief Engineer of Mines and Inspector General of Mines, becoming Dean of the Ecole Nationale des Mines in 1901-1907, when he retired.
Carnotite Group.

A secondary mineral resulting from the alteration of Uraninite, Montroseite, or Davidite. Occurs in sandstones, especially in paleochannels, near fossil carbonaceous matter, in calcretes and near playas.

Classification of Carnotite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
4.HB.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
B : Uranyl Sorovanodates
40.2a.28.1

40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2a : AB2(XO4)2·xH2O, containing (UO2)2+
21.4.4

21 : Vanadates (and vanadates with arsenate or phosphate)
4 : Vanadates of U, Mn, Fe or Ni
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Type Occurrence of Carnotite

Place of Conservation of Type Material:
University of Colorado, Boulder, Colorado: #2218. Harvard University, Cambridge, Massachusetts, USA: #106253.
Year of Discovery:
1899
Geological Setting of Type Material:
Colorado Plateau sedimentary vanadium-uranium deposits

Occurrences of Carnotite

Geological Setting:
Colorado Plateau type uranium deposits, near playas.

Physical Properties of Carnotite

Sub-Vitreous, Resinous, Waxy, Silky, Dull, Earthy
Diaphaneity (Transparency):
Translucent
Comment:
Silky to waxy when crystalline
Colour:
Bright yellow, yellow, greenish yellow
Comment:
Easily stained when fine-grained
Streak:
Strontian-yellow
Hardness (Mohs):
2
Tenacity:
Fragile
Cleavage:
Perfect
on {001}, perfect, micaceous
Fracture:
Micaceous
Density:
4.70 g/cm3 (Measured)    4.91 g/cm3 (Calculated)
Comment:
Earthy material lower in compactness

Crystallography of Carnotite

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Space Group Setting:
P21/a
Cell Parameters:
a = 10.47Å, b = 8.41Å, c = 6.91Å
β = 103.83°
Ratio:
a:b:c = 1.245 : 1 : 0.822
Unit Cell Volume:
V 590.80 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals rare, diamond-shaped, flattened {001} and rhomboidal {110}, also lath-like [010] with {100} and {110} or {120}; (110) ^ (110) ~78°; commonly as fine aggregates or pulverulent; disseminated, compact massive.
Twinning:
On {001} as both the composition and twin plane.
Comment:
Space group determined based on synthetic, anhydrous material.
X-Ray Powder Diffraction Data:
d-spacingIntensity
6.56 (100)
4.25 (30)
3.53 (50)
3.25 (30)
3.12 (70)
2.571 (20)
2.156 (30)
(

Optical Data of Carnotite

Type:
Biaxial (-)
RI values:
nα = 1.750 nβ = 1.925 nγ = 1.950
2V:
Measured: 43° to 60°, Calculated: 26° to 36°
Birefringence:
0.200
Max Birefringence:
δ = 0.200
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Very High
Dispersion:
r < v
Optical Extinction:
Z^a ~14°; X=c, Y=b
Pleochroism:
Weak
Comments:
X = Nearly colourless to pale grayish yellow
Y = Z = Canary yellow, lemon-yellow
Comments:
Indices of refraction increase as water content decreases.

Chemical Properties of Carnotite

Formula:
K2(UO2)2(VO4)2 · 3H2O
Essential elements:
All elements listed in formula:

Relationship of Carnotite to other Species

Member of:
Other Members of Group:
SengieriteCu2(UO2)2(VO4)2 · 6H2O
StrelkiniteNa2(UO2)2(VO4)2 · 6H2O
TyuyamuniteCa(UO2)2(VO4)2 · 5-8H2O
4.HB.05Margaritasite(Cs,K,H3O)2(UO2)2(VO4)2 · H2O
4.HB.10SengieriteCu2(UO2)2(VO4)2 · 6H2O
4.HB.15CurienitePb(UO2)2(VO4)2 · 5H2O
4.HB.15Francevillite(Ba,Pb)(UO2)2(VO4)2 · 5H2O
4.HB.15FritzscheiteMn(UO2)2(PO4,VO4)2 · 10H2O (?)
4.HB.20MetavanuraliteAl(UO2)2(VO4)2(OH) · 8H2O
4.HB.20VanuraliteAl(UO2)2(VO4)2(OH) · 11H2O
4.HB.25MetatyuyamuniteCa(UO2)2(VO4)2 · 3-5H2O
4.HB.25TyuyamuniteCa(UO2)2(VO4)2 · 5-8H2O
4.HB.30StrelkiniteNa2(UO2)2(VO4)2 · 6H2O
4.HB.35UvaniteU26+V65+O21 · 15H2O (?)
4.HB.40RauviteCa(UO2)2(V10O28) · 16H2O
21.4.1UvaniteU26+V65+O21 · 15H2O (?)
21.4.2Vanuranylite(H3O)2(UO2)2(VO4)2 · 4H2O
21.4.3StrelkiniteNa2(UO2)2(VO4)2 · 6H2O
21.4.5Margaritasite(Cs,K,H3O)2(UO2)2(VO4)2 · H2O
21.4.6SengieriteCu2(UO2)2(VO4)2 · 6H2O
21.4.7MetatyuyamuniteCa(UO2)2(VO4)2 · 3-5H2O
21.4.8TyuyamuniteCa(UO2)2(VO4)2 · 5-8H2O
21.4.9RauviteCa(UO2)2(V10O28) · 16H2O
21.4.10Francevillite(Ba,Pb)(UO2)2(VO4)2 · 5H2O
21.4.11MetavanuraliteAl(UO2)2(VO4)2(OH) · 8H2O
21.4.12VanuraliteAl(UO2)2(VO4)2(OH) · 11H2O
21.4.13CurienitePb(UO2)2(VO4)2 · 5H2O
21.4.14FritzscheiteMn(UO2)2(PO4,VO4)2 · 10H2O (?)
21.4.15Palenzonaite(Ca,Na)3CaMn22+(VO4)3
21.4.16Santafeite(Na,Ca,Sr)12(Mn2+,Fe3+,Al,Mg)8Mn84+(VO4)16(OH,O)20 · 8H2O
21.4.17PyrobelonitePbMn2+(VO4)(OH)
21.4.18BrackebuschitePb2Mn3+(VO4)2(OH)
21.4.19ČechitePb(Fe2+,Mn2+)(VO4)(OH)
21.4.20HeyitePb5Fe22+(VO4)2O4
21.4.21MounanaitePbFe23+(VO4)2(OH,F)2
21.4.22SchubneliteFe3+VO4 · H2O
21.4.23FervaniteFe43+V45+O16 · 5H2O
21.4.24KazakhstaniteFe53+V34+V125+O39(OH)9 · 9H2O
21.4.25Bokite(Al,Fe3+)1.3(V5+,V4+,Fe3+)8O20 · 7.4H2O
21.4.26Rusakovite(Fe3+,Al)5(VO4,PO4)2(OH)9 · 3H2O
21.4.27KolovratiteNixZny(VO4)0.67(x+y) · nH2O

Other Names for Carnotite

Name in Other Languages:
German:Carnotit
Simplified Chinese:钒钾铀矿
钒酸钾铀矿
Spanish:Carnotita
Traditional Chinese:釩鉀鈾礦
釩酸鉀鈾礦

Other Information

Other Information:
Radioactive. Water content is partly zeolitic and varies with humidity at ambient temperatures. Readily soluble in acids.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Uranium ore

References for Carnotite

Reference List:
Friedel and Cumenge (1899) Comptes rendus de l’Académie des sciences de Paris: 128: 532.

Friedel and Cumenge (1899) Bulletin de la Société française de Minéralogie: 22: 26.

Acta Crystallographica: 10: 765.

Doelter, C. (1918) Handbuch der Mineral-chemie (in 4 volumes divided into parts): 3 [I]: 844.

Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679: 52.

Crook and Blake (1924) Mineralogical Magazine: 15: 271.

Hillebrand (1924)American Journal of Science: 8: 201.

Hess and Foshag (1927) Proceedings of the U.S. National Museum: 72, Art. 12.

Hintze, Carl (1931) Handbuch der Mineralogie. Berlin and Leipzig. 6 volumes: 1 [4B]: 1002.

Sundberg and Sillén (1949) Arkiv för Kemi, Mineralogi och Geologi, Stockholm: 1, no. 42: 337.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 1043-1045.

Frondel, C. (1958) Systematic mineralogy of uranium and thorium. U.S. Geological Survey Bull. 1064, 243–247.

Appleman, D.E. and H.T. Evans, Jr. (1965) The crystal structures of synthetic anhydrous carnotite, K2(UO2) V2O8, and its cesium analogue, Cs2(UO2)2V2O8. American Mineralogist: 50: 825–842.

Anthony, J.W., Bideaux, R.A., Bladh, K.W., and Nichols, M.C. (2000) Handbook of Mineralogy, Volume IV. Arsenates, Phosphates, Vanadates. Mineral Data Publishing, Tucson, AZ, 680pp.: 96.

Internet Links for Carnotite

Specimens:
The following Carnotite specimens are currently listed for sale on minfind.com.

Localities for Carnotite

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Mineral and/or Locality  
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