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Umohoite

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About UmohoiteHide

Formula:
(UO2)MoO4 · 2H2O
Colour:
Black, blue-black, dark green
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
4.53 - 4.66
Crystal System:
Triclinic
Name:
The name reflects its composition: uranyl (U), molybdate (Mo) and water (H2O).
This page provides mineralogical data about Umohoite.


Classification of UmohoiteHide

Approved, 'Grandfathered' (first described prior to 1959)
4.GC.10

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
G : Uranyl Hydroxides
C : With additional cations; with mainly UO2(O,OH)6 hexagonal polyhedra
49.2.2.1

49 : HYDRATED MOLYBDATES AND TUNGSTATES
2 : Hydrated Normal Molybdates and Tungstates
27.3.8

27 : Sulphites, Chromates, Molybdates and Tungstates
3 : Molybdates

Physical Properties of UmohoiteHide

Vitreous
Transparency:
Opaque
Colour:
Black, blue-black, dark green
Hardness:
Cleavage:
Perfect
Perfect on {001}
Density:
4.53 - 4.66 g/cm3 (Measured)    4.49(3) g/cm3 (Calculated)

Optical Data of UmohoiteHide

Type:
Biaxial (-)
RI values:
nα = 1.660 nβ = 1.831 nγ = 1.915
2V:
Measured: 65° , Calculated: 64°
Max Birefringence:
δ = 0.255
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High
Dispersion:
weak r>v
Pleochroism:
Visible
Comments:
X= dark blue
Y= pale blue
Z= olive-green

Chemical Properties of UmohoiteHide

Formula:
(UO2)MoO4 · 2H2O
IMA Formula:
(UO2)(MoO4) · 2H2O

Crystallography of UmohoiteHide

Crystal System:
Triclinic
Cell Parameters:
a = 14.6 Å, b = 7.5 Å, c = 6.38 Å
β = 99.08°
Ratio:
a:b:c = 1.947 : 1 : 0.851
Unit Cell V:
nan ų (Calculated from Unit Cell)
Z:
4
Morphology:
Tabular plates, rosettes, massive, disseminated, thin veinlets
Comment:
pseudorhombohedral

Type Occurrence of UmohoiteHide

Other Language Names for UmohoiteHide

German:Umohoit
Spanish:Umohoita

Common AssociatesHide

Associated Minerals Based on Photo Data:
Calcurmolite14 photos of Umohoite associated with Calcurmolite on mindat.org.
Iriginite7 photos of Umohoite associated with Iriginite on mindat.org.
Uranophane-β6 photos of Umohoite associated with Uranophane-β on mindat.org.
Baryte4 photos of Umohoite associated with Baryte on mindat.org.
Uranophane2 photos of Umohoite associated with Uranophane on mindat.org.
Ianthinite1 photo of Umohoite associated with Ianthinite on mindat.org.
Vanmeersscheite1 photo of Umohoite associated with Vanmeersscheite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.GC.05Clarkeite(Na,Ca,Pb)(UO2)O(OH) · 0-1H2OTrig.
4.GC.15SpriggitePb3(UO2)6O8(OH)2 · 3H2OMon. 2/m

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

27.3.1LindgreniteCu3(MoO4)2(OH)2Mon. 2/m : P21/m
27.3.2PowelliteCa(MoO4)Tet. 4/m : I41/a
27.3.3WulfenitePb(MoO4)Tet. 4/m : I41/a
27.3.4KoechliniteBi2MoO6Orth. mm2 : Pna21
27.3.5SedoviteU(MoO4)2Orth.
27.3.6MouriteUMo5O12(OH)10Mon.
27.3.7Iriginite(UO2)Mo2O7 · 3H2OOrth. mmm (2/m 2/m 2/m) : Pbcm
27.3.9MoluraniteH4U4+(UO2)3(MoO4)7 · 18H2O
27.3.10CousiniteMgU2Mo2O11 · 6H2O
27.3.11Calcurmolite(Ca,Na)2(UO2)3Mo2(O,OH)11 · nH2O
27.3.12TengchongiteCaO · 6UO3 · 2MoO3 · 12H2OOrth.
27.3.13KamiokiteFe2Mo3O8Hex.
27.3.14FerrimolybditeFe2(MoO4)3 · nH2OOrth. mmm (2/m 2/m 2/m) : Pmmn

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for UmohoiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Brophy, G.P. & Kerr, P.F. (1953): Hydrous uranium molybdate in Marysvale ore. Annual Report June 30, 1952 - April 1, 1953 U.S.Atomic Energy Comm., RME-3046, 45-51.
Rocks and Minerals (1953): 28: 480.
American Mineralogist (1957): 42: 657-660.
Makarov, E.S. and Anikina, L.I. (1963) Crystal structure of umohoite [UMoO6(H2O)2]·2H2O. Geochemistry: 14-21.
Krivovichev, S.V. and Burns, P.C. (2000a) Crystal chemistry of uranyl molybdates. I. The structure and formula of umohoite. Canadian Mineralogist: 38: 717-726.
Burns, P.C. (2005) U 6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. Canadian Mineralogist: 43: 1839-1894.

Internet Links for UmohoiteHide

Localities for UmohoiteHide

ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Democratic Republic of the Congo
 
  • Katanga (Shaba)
    • Kambove District
      • Shinkolobwe
[MinRec 20:286-287]
Egypt
 
  • South Sinai Governorate
    • Abu Zeneima (Abu Zenima)
Bisher, A. H. (2012). Primary uranium mineralization in paleochannels of the Um Bogma formation at Allouga Southwestern Sinai. Eleventh Arab Conference on the Peaceful Uses of Atomic Energy. Khartoum. Sudan. 16-20 December 2012
France
 
  • Occitanie
    • Hérault
      • Le Bosc
Le Règne Minéral, Hors Série IV (1998)
      • Le Puech
[MinRec 25:209, 23:433]; Bariand, P., Bachet, B., Brassy, C., Medenbach, O., Deliens, M., Vautier, R., & Piret, P. (1993) A New Uranium Mineral from the Talmessi Mine, Iran, and Rabejac, France. Mineralogical Record: 24: 463-467
      • Lodève
[Le Cahier des Micromonteurs, 1998, 2, p.13-26]
Kazakhstan
 
  • Zhambyl
    • Chu-Ili Mts
Can Min 38:717-726; Pekov, I. (1998) Minerals First discovered on the territory of the former Soviet Union 369p. Ocean Pictures, Moscow
USA
 
  • Arizona
    • Coconino Co.
      • Cameron District
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 289, 406; Hamilton, P. & P.F. Kerr (1959), Umohoite from Cameron, AZ, Am.Min.: 44: 1248-1260; Keith (1970), AZ Bur. Mines Bull. 182: 103-159, 202-289; Bollin & Kerr (1958), Guidebook for New Mexico Geol.Soc., 9th. Field Conference F.P. 164-168.
  • New Mexico
    • Guadalupe Co.
Minerals of New Mexico 3rd ed.
  • Texas
    • Live Oak Co.
R&M 66:3 pp 196-224
Econ Geol (1986) 81:131-142
  • Utah
    • Piute Co.
      • Antelope Range
        • Henry District (Durkee District)
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
Page, L. R.; Stocking, H. E.; Smith, H. B. (1956) Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations International Conference on Peaceful Uses of Atomic Energy, Geneva, Switzerland, 1955. USGS Professional Paper 300 pp97-103
UGMS Bull 117 Minerals and Mineral Localities of Utah
Handbook of Mineralogy - Anthony, Bideaux, Bladh, Nichols
    • Sevier Co.
      • Gold Mountain District
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
  • Wyoming
    • Fremont Co.
      • Gas Hills District
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
Can Min 38:717-726
Mineral and/or Locality  
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