Uranopilite

 IMA-GP
Uranium 31.2.6.1
(Dana Classification Number)
(Images) 6/D.20-10
(Strunz ID)
Unless sealed in glass, all specimens should be considered to have become Meta-Uranopilite within a few months of being exposed to ambient air.

Property Data Remarks
Named for: Its Uranium content and the Greek for "felt", refering to its habit
Alternate
    Name(s):
  		•  
    Mineral Class:
    Sulfates, Chromates, Molybdates and Tungstates
      Uranylsulfates [UO2]+2 - [SO4]-2
        Uranopilite - Rabejacite series
    		 
    Chemical
        Formula:    		 [(UO2)6(SO4)O2(OH)6(H2O)6] · 8H2O  
    Chemical
        Composition:
    Hydrogen: (H) 1.63%
    Oxygen: (O) 28.92%
    Sulfur: (S) 1.53%
    Uranium: (U) 67.93%
    		by weight
    Molecular
        Weight:    		 2,102.49 daltons (amu)
    Specific
        Radioactivity:

    (All radiation is for a 1 gram, fully aged specimen)

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.21591 × 1005 3.29 × 10-06 1.64 164.06

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Triclinic - Pinacoidal
        (also listed as monoclinic)
    Axial Ratios: a:b:c =0.6341:1:1.022
    Cell Dimensions: a = 8.896, b = 14.029, c = 14.339, Z = 2; alpha = 96.61°, beta = 98.472°, gamma = 99.802° V = 1,732.58 Den(Calc) = 4.03
    H-M Symbol: -1
    Space Group: P-1
    X Ray Diffraction: By Intensity(I/Io): 7.12(1) 4.28(0.8) 9.18(0.8)
    		Uranopilite
    Crystal
    Habit:
  • Usually limited to encrustations and compact masses
  • Reniform
    		•   
    Cleavage: None  
    Fracture:    
    Moh's
        Hardness:    		 2  
    Density: 3.7 - 4.0 grams/cm3
    Color: Bright shades of Yellow  
    Streak: Pale yellow  
    Luster: Silky  
    Diaphaneity: Transparent to Translucent  
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:
    Long Wave: Bright greenish yellow
    Short Wave: Bright greenish yellow
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Secondary mineral found on altering uraninite
  		•   
    Associated
        Minerals:

    Aragonite, Arsenopyrite, Autunite, Azurite, Barite, Becquerelite, Bismuth, Bornite, Calcite, Cerussite, Chalcocite, Chalcopyrite, Chrysocolla, Coffinite, Copper, Covellite, Dolomite, Erythrite, Fluorite, Galena, Goethite, Gypsum, Hematite, Johannite, Malachite, Marcasite, Metatorbernite, Novácekite, Pyrite, Quartz, Schoepite, Siderite, Sphalerite, Tetrahedrite, Torbernite, Uraninite, Uranophane, Zeunerite, Zippeite

    Mineral   -   > 67% of sites
    Mineral   -   > 50% of sites
    Mineral   -   > 26% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Uranopilite
    Locations:

    Rare

    Uranopilite Locations
    Notes:

    Strongly radioactive a- and b-particles, g-rays.

    Crystals are probably metamict.

    Uranopilite Images

    Specimen #1
    (001a) (001b) (001c) (001d)

     
    (001e) (001f) (001g) (001h)

     
     
    (001i) (001j) (001k) (001l)

     
     
    (001m) (001n) (Johannite-001c)

     
    Apex Mine, Lander Co., Nevada, U.S.A.


    Specimen Notes

    Source - The following minerals are confirmed as occurring at this mine: Autunite, Meta-autunite, Meta-Torbernite, Torbernite, Uranopilite, and Zippeite. This specimen also shows that Aragonite and Johannite to also be present.

    Occurrence - Both Uranopilite and Johannite occur in proximity to each other, often either growing on each other, or totally intergrown. In the upper right corner of image 001a, the Uranopilite can be seen to have grown on the Johannite, and later overgrown by the Johannite, so the clusters of Uranopilite became encased in the Johannite.

    The chemical composition of Johannite and Uranopilite differ primarily in that the Johannite includes copper in its composition. Otherwise, they are very much alike, chemically. This likely accounts for their co-occurrance on the specimen, even though Johannite is not listed as a recognized mineral occurance at this site. The Uranopilite was likely deposited when the mother liqure was depleated of, or lacking, copper.

    In images 001g, 001h, 001l (best) and 001m, microcrystals of what is believed to be Cuprosklodowskite on white Aragonite can be seen. While Sklodowskite is possible, the presence of a copper mineral (Johannite) makes this unlikely.

    The host rock is limestone that is partially metamorphosed into marble, as can be seen in images 001f and Johannite-001c. The limestone/marble has a definite grain to it, as the fracture with the grain is quite smooth, while that across the grain if very uneven. In places, the conversion to marble is quite obviously incomplete, with whiteish lime between grains of Aragonite. This can best be seen in image 001c. The occurance of both Johannite and Uranopilite on limestone/marble is in accordance with the hot radicals theory of the crystalization of uranyl minerals.

    In images 001a through 001c, the Uranopilite occurs as loose clusters on a substrate of thin, massive Johannite. In image 001d, the the Uranopilite occurs directly on the limestone/marble host rock. In image 001e, it appears to occur on a mixed bed of Johannite and Uranopilite. The crystal clusters in image 001c appear, due to color, to be a mixture of both Johannite and Uranopilite.

    Crystals - The crystals all occur in roughly rounded clusters. The crystal growth is uneven, giving the clusters their lumpy appearance. The crystals are acicular, and almost all microcrystals, with the larger crystals being under 0.1 mm in length. A rare crystal of the basic Triclinic - Pinacoidal form can be seen in the lower center cluster of image 001b.

    Diaphaneity - The crystals of Uranopilite are transluscent, and approach being opaque.

    Luster - The larger crystals are vitreous in luster, with the microcrystals having a silky to earthy luster.

    Specimen Physical Properties
    Weight: 215.41 grams    
    g-Radiation Level: 43 cmp 4.3 msieverts background: 20 cpm