Bismutopyrochlore

 IMA-A 1998-059
Uranium 8.2.1.9
(Dana Classification Number)
(No Images) 4/C.17-85
(Strunz ID)

Property Data Remarks
Named for: Its composition and relationship to pyrochlore
Alternate
    Name(s):
  		•  
    Mineral Class:
    Oxides & Hydroxides
      Oxides with metal: (metal:oxygen = 2:3 - M2O3 and related compounds)
        Pyrochlore group (Pyrochlore series with Nb > Ti)
    		 
    Chemical
        Formula:    		 (Bi,U,Ca,Pb)1+x(Nb,Ta)2O6(OH) · nH2O  
    Chemical
        Composition:
    Bismuth: (Bi) 14.85%
    Calcium: (Ca) 2.14%
    Hydrogen: (H) 1.72%
    Lead: (Pb) 3.68%
    Niobium: (Nb) 24.76%
    Oxygen: (O) 32.12%
    Tantalum: (Ta) 8.04%
    Uranium: (U) 12.69%
    		by weight
    Molecular
        Weight:    		 562.81 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    2.2711 × 1004 6.14 × 10-07 0.32 32.19

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Isometric - Hexoctahedral
    Axial Ratios: a:  
    b:  
    c:  
    Cell Dimensions: a: 10.41 Å
    Z: 6
    V: 1,128.11 Å3
    DenCalc: 4.97
    H-M Symbol: 4/m -3 2/m
    Space Group: Fd3m
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 2.967 Å
    (0.9): 1.569 Å
    (0.9): 1.848 Å
    (0.8): 1.195 Å
    (0.7): 2.614 Å
    (0.5): 1.145 Å
    (0.4): 1.5 Å
    (0.4): 5.98 Å
    		Bismutopyrochlore
    Crystal
    Habit:
  • Crystalline - usually metamict
  • Amorphous
    		•   
    Cleavage: None  
    Fracture: Brittle - Conchoidal  
    Moh's
        Hardness:    		 5  
    Density: 4.97 grams/cm3
    Color: Brownish green, black  
    Streak: Yellow  
    Luster: Adamantine - Vitreous  
    Diaphaneity: Translucent  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:  
    Short Wave:  
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Formed on lepidolite in miarolitic cavities in a pegmatite vein
    		•   
    Associated
        Minerals:

    Albite, 'Apatite', Barite, Beryl, Calcite, Cassiterite, Elbaite, Fluorite, Hambergite, Lepidolite, Microcline, Muscovite, Quartz, Schorl, Topaz

    		 These are minerals known to be found with Bismutopyrochlore
    Localities:

    Extremely rare

    Bismutopyrochlore Localities
    Notes:

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

    Crystals are probably metamic.