Walpurgite

 IMA-GP
Uranium 40.5.9.1
(Dana Classification Number)
(Images) 7/E.10-20
(Strunz ID)

Property Data Remarks
Named for: Walpurgis Vein at Walpurgis Flats, Weißer Hirsch Mine, Neustädtel, Schneeberg District, Johanngeorgenstadt, Erzgebirge, Saxony, Germany, its type locality
Alternate
    Name(s):
  • Walpurgit
  • Walpurgita
    		•   
    Mineral Class:
    Phosphates, Arsenates and Vanadates
      Uranylphosphates and uranylvanadates with
    [UO2]2+ - [PO4 | AsO4]3- and [UO2]2+ - [V2O8]6-
        Asselbornite - Walpurgite series
    		 
    Chemical formula: (BiO)4UO2(AsO4)2 · 1-2H2O  
    Chemical
        Composition:
    Arsenic: (As) 10.10%
    Bismuth: (Bi) 56.34%
    Hydrogen: (H) 0.27%
    Oxygen: (O) 17.25%
    Uranium: (U) 16.04%
    		by weight
    Molecular
        Weight:    		 1,483.82 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    2.8715 × 1004 7.76 × 10-07 0.38 37.69

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Triclinic - Pinacoidal
    Axial Ratios: a:b:c = 0.6829:1:0.5258
    Cell Dimensions: a = 7.13, b = 10.44, c = 5.49, Z = 1; alpha = 104.667°, beta = 110.817°, gamma = 88.283° V = 369.37 Den(Calc)= 6.67
    H-M Symbol: -1
    Space Group: P-1
    X Ray Diffraction: By Intensity(I/Io): 3.11(1) 3.05(0.5) 3.25(0.5)
    		 
    Habit: Platy elongated crystals often aggregated and twinned. Also as crusts, fibrous and earthy.  
    Cleavage: Perfect
    [001]
    [010] Perfect
    [100]

    Cleavage sheets are very brittle
    Fracture: Lamellar - Brittle  
    Moh's
        Hardness:    		 3.5  
    Density: 5.95 - 6.69 grams/cm3
    Color: Yellow, but can be a reddish orange  
    Streak: Pale yellow to Yellow white  
    Luster: Adamantine - Greasy - Waxy  
    Diaphaneity: Transparent to Translucent  
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:    		 Non-fluorescent (One Specimen Examined)
    Magnetism: Non-magnetic  
    Occurance:
  • Granitic pegmatite
  		•   
    Associated
        Minerals:    		 Bismutite, Torbernite, Zeunerite, Uraninite and other uranium minerals.  
    Locations:

    Very rare

    Walpurgite Locations
    Notes:

    Radioactive: a- and b-particles, g-rays.

    Unusual chemistry, having Arsenic, Bismuth and Uranium. Too rare to be considered an ore.

    Walpurgite Images

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

    3 x 2 x 2 cm
    Weißer Hirsch Mine, Neustädtel, Schneeberg District, Erzgebirge, Saxony, Germany