Oswaldpeetersite

 IMA-A 2000-034
Uranium 15.1.8.3
(Dana Classification Number)
(Images) 5F.01-30
(Strunz ID)

Property Data Remarks
Named for: Maurice Oswald Peeters(1945-), structural crystallographer University of Leuven, Belgium
Alternate
    Name(s):
  • Oswaldpeetersit
  • Oswaldpeetersita
    		•   
    Mineral Class:
    Nitrates, Carbonates and Borates
      Uranylcarbonates ([UO2]+2 - [CO3]-2)
        Rutherfordine - Joliotite series
    		 
    Chemical
        Formula:    		 (UO2)2CO3(OH)2 · 4H2O  
    Chemical
        Composition:
    Carbon: (C) 1.70%
    Hydrogen: (H) 1.43%
    Oxygen: (O) 29.45%
    Uranium: (U) 67.42%
    		by weight
    Molecular
        Weight:    		 706.14 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.20676 × 1005 3.26 × 10-06 1.63 162.67

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Monoclinic - Prismatic
    Axial Ratios: a: 0.2938
    b: 1
    c: 1.3033
    Cell Dimensions: a: 4.1425 Å
    b: 14.098 Å
    c: 18.374 Å
    Z: 4
    b: 103.62°
    V: 1,042.88 Å3
    DenCalc: 4.54
    H-M Symbol: 2/m
    Space Group: P21/c
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 3.322 Å
    (0.96): 4.546 Å
    (0.85): 3.029 Å
    (0.65): 8.95 Å
    (0.63): 7.54 Å
    (0.62): 2.273 Å
    (0.62): 3.463 Å
    (0.6): 4.262 Å
    		 
    Habit:
    • Prismatic
    • Microcrystaline, crystals tend to be under 0.1 mm long and 0.01 mm wide
    • Radiating groups
    • Heavily striated parallel to the length
    		  
    Cleavage:
    [hk0] Distinct
    		 
    Fracture: Weak and Uneven - easily damaged  
    Moh's
        Hardness:    		 2 - 3  
    Density: 4.10 - 4.55 grams/cm3
    Color: Canary-yellow  
    Streak: Pale yellow  
    Luster: Vitreous  
    Diaphaneity: Transparent  
    Pleochroism:
    (x): Very pale yellow to colorless
    (y:) Very pale yellow to colorless
    (z:) Pale yellow
    		 
    Ultra Violet
        Fluorescence:    		 None  
    Magnetism: Non-magnetic  
    Occurance:
    • Along some bedding planes of siltstone within a layer of sandstone in organic-rich Permian-aged (Triassic) Shinarump Conglomerate
    • Shinarump Conglomerate in a fossilized log
    		  
    Associated
        Minerals:

    Alunite, Anhydrite, Antlerite, Asbolane, Azurite, Birnessite, Blatonite, Boltwoodite, Brochantite, Carbonate-cyanotrichite, Chalcanthite, Chalcocite, Chalcopyrite, Coconinoite, Compreignacite, Cuprite, Goethite, Gypsum, Hematite, Hydrombobomkulite, Hydronium jarosite, Jarosite, Lepidocrocite, 'Limonite', Malachite, Mbobomkulite, Meta-Autunite, Metaschoepite, Metazeunerite, Pyrite, Quartz var: Petrified Wood, Rutherfordine, Schoepite, Serpierite, Sklodowskite, Smithsonite, Sphalerite, Swamboite, Uraninite, Uranopilite, and two undefined uranium minerals

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Oswaldpeetersite
    Locations:

    Extremely rare

    Oswaldpeetersite Locations
    Notes:

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

    Crystals are probably metamic.

    Oswaldpeetersite Images

    Specimen 1

    (#21 of 21 specimens known - Part of original find)
    (001a) (001b) (001c) (001d)
    Jomac Mine, San Juan County, Utah, U.S.A.
    (Metatype specimens from the one pocket collected on 8/28/1999
    Fewer than 30 specimens are known)


    Specimen Notes

    Habit - Oswaldpeetersite forms radial clusters of microcrystals on a substrate of Aragonite or Calcite. This is consistant with the observed habit of uranium minerals containing compact anions (halides, hydroxide) to prefere a calcium carbonate (CaCO3) substrate, and avoid a silicate substrate. The color of these microcrystals appears pale due to the high reflectance of these crystals.

    Substrates - The Aragonite, beside being a substrate for the Oswaldpeetersite, also forms stalagmites between the upper and lower sides of the crack in which the Oswaldpeetersite formed. These appear as blurred nebula in the images. The stalagmites are densely scattered in the upper left quadrant of image 001a, and a particularly large one, possibly several conjoined stalagmites, appears in the center of the lower left quadrant of the same image. Located at just above the exact center of image 001d is a free standing stalagmite in profile. These staglagmites vary from thin needles to thick trunks. It is these stalagmites that indicate that the plane of the Oswaldpeetersite deposit was generally horizontal.

    Many are connected at the top by a layer of aragonite which was likely a substrate on the removed, corresponding, host rock layer. Extending from the lower right corner to the bottom center in image 001c is part of a large plate of Aragonite supported by Aragonite stalagmites, which appear as milkier blobs under the plate.

    Image 001d shows the Aragonite substrate and stalgmites are on a second substrate of what appears to be a platey layer of Anhydrite. This Anhydrite layer appears to be angled, but is actually oriented vertically between the Aragonite substrate and the silicate host rock. It is oriented at an angle to the edge of the specimen, giving it its slanted appearence.

    Crystals - The crystals of Oswaldpeetersite form radial clusters similar to those of Boltwoodite, but considerably smaller. The crystals, seen under 30X magnification, are acicular, but are so small that their crystal form is not visable at this magnification. There is no observable seed or other cause for these clisters, as can be ocassionally be seen in the Haynesite image 001l.

      -  

     

    Physical Properties
    Size   cm   cm   cm
    Weight: 28.48 grams    
    g-Radiation Level: Too little radiation to register on a geiger counter background: 22 cpm
           
     

     

    Jomac Mine, San Juan County, Utah, U.S.A.
    		 Jomac Mine, San Juan County, Utah, U.S.A.
    (These four images courtesy of Dr. Rob Lavinsky of The Arkenstone)