Uranophane
General
CategoryUranyl neso- and polysilicates
Formula
(repeating unit)
Ca(UO2)2[HSiO4]2·5H2O
IMA symbolUrp-α[1]
Strunz classification9.AK.15
Crystal systemMonoclinic
Crystal classSphenoidal (2)
(same H-M symbol)
Space groupP21
Unit cella = 15.85 Å, b = 6.98 Å
c = 6.64 Å; β = 97.45°; Z = 2
Identification
Formula mass586.36 g/mol
ColorLight yellow, lemon-yellow, honey-yellow, straw-yellow, green-yellow
Crystal habitCrystals occur as stellate needle aggregates; as fibrous crusts, and massive
Cleavage{100} Perfect
FractureUneven
TenacityBrittle
Mohs scale hardness2.5
LusterVitreous to pearly; waxy or dull when massive
StreakYellowish white
DiaphaneityTranslucent to subtranslucent
Specific gravity3.81 - 3.90
Optical propertiesBiaxial (-)
Refractive indexnα = 1.643 nβ = 1.666 nγ = 1.669
Birefringenceδ = 0.026
PleochroismWeak; X = colorless; Y = pale canary-yellow; Z = canary-yellow
2V angle32° to 45°, measured
Ultraviolet fluorescenceWeak yellow-green under both short and long UV
Other characteristics Radioactive
References[2][3][4]

Uranophane (Ca(UO2)2(SiO3OH)2·5H2O), also known as uranotile, is a rare calcium uranium silicate hydrate mineral that forms from the oxidation of other uranium-bearing minerals. It has a yellow color and is radioactive.

Alice Mary Weeks, and Mary E. Thompson of the United States Geological Survey, identified uranophane in 1953.[5]

Classic samples have been produced at Madawaska Mine near Bancroft, Ontario.[6]

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. Handbook of Mineralogy
  3. Uranophane on Mindat.org
  4. Uranophane on Webmineral
  5. Moore, James Gregory (1963). Geology of the Mount Pinchot Quadrangle, Southern Sierra Nevada, California. U.S. Government Printing Office.
  6. McDougall, Raymond (2019-09-03). "Mineral Highlights from the Bancroft Area, Ontario, Canada". Rocks & Minerals. 94 (5): 408–419. doi:10.1080/00357529.2019.1619134. ISSN 0035-7529. S2CID 201298402.


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