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About UmohoiteHide

(UO2)MoO4 · 2H2O
Black, blue-black, dark green
Specific Gravity:
4.53 - 4.66
Crystal System:
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 : 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

2 : Hydrated Normal Molybdates and Tungstates

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

Physical Properties of UmohoiteHide

Black, blue-black, dark green
Perfect on {001}
4.53 - 4.66 g/cm3 (Measured)    4.49(3) g/cm3 (Calculated)

Optical Data of UmohoiteHide

Biaxial (-)
RI values:
nα = 1.660 nβ = 1.831 nγ = 1.915
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
weak r>v
X= dark blue
Y= pale blue
Z= olive-green

Chemical Properties of UmohoiteHide

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

Crystallography of UmohoiteHide

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

Type Occurrence of UmohoiteHide

Other Language Names for UmohoiteHide


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
27.3.7Iriginite(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.
27.3.14FerrimolybditeFe2(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

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - 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.
DR Congo
  • Haut-Katanga
    • Kambove District
      • Shinkolobwe
[MinRec 20:286-287]
  • South Sinai
    • 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
  • 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; Dal Bo, F., Hatert, F., & Philippo, S. (2018). Supergene Uranyl Mineralization of the Rabejac Deposit, Lodève, France. Minerals, 8(9), 414.
      • Lodève
[Le Cahier des Micromonteurs, 1998, 2, p.13-26]
  • Sumatra
    • Sumatera Utara Province (North Sumatra Province)
Setiawan I, Takahashi R, Imai A (2014) Hydrothermal alteration and base metal-REE mineralization in granitoids at Panyabungan and its surroundings of North Sumatra, Indonesia. 21 st meeting of the International Mineralogical Association.
  • Jambyl Region
    • Moiynkum
      • 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
  • 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 Mining 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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