Davidite-(La)

 IMA-GP
Uranium
(Minor)		 8.5.1.5
(Dana Classification Number)
(Images) 4/C.09-60
(Strunz ID)

Property Data Remarks
Named for: Tenatt William Edgeworth David(1858-1934), Australian geologist, and its composition
Alternate
    Name(s):
  		•  
    Mineral Class:
    Oxides
      Oxides with metal: (metal:oxygen = 2:3 (M2O3 and related compounds)
        Crichtonite group
    		 
    Chemical
        Formula:    		 (La,Ce,Ca)(Y,U)(Ti,Fe+3)20O38  
    Chemical
        Composition:
    Calcium: (Ca) 0.22%
    Cerium: (Ce) 1.51%
    Iron: (Fe) 15.01%
    Lanthanum: (La) 5.23%
    Oxygen: (O) 32.67%
    Titanium: (Ti) 38.59%
    Yttrium: (Y) 3.58%
    Uranium: (U) 3.20%

    by weight

     

    (composition varries)
    Molecular
        Weight:    		 1,860.86 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    5.875 × 1003 1.59 × 10-07 0.09 8.60

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Trigonal - Rhombohedral
    Axial Ratios: a: 1
    c: 2.01522
    Cell Dimensions: a: 10.376 Å
    c: 20.91 Å
    Z: 3
    V: 1,949.60 Å3
    DenCalc: 4.75
    H-M Symbol: -3
    Space Group: R-3
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 2.895 Å
    (0.72): 3.42 Å
    (0.6): 2.85 Å
    		 
    Habit:
  • Anhedral Grains
  • Massive
    		•   
    Cleavage: None  
    Fracture: Conchoidal - very brittle  
    Moh's
        Hardness:    		 6  
    Density: 4.42 grams/cm3
    Color: Black, Grayish black, Brownish black, dark Brown, or Reddish  
    Streak: Brownish black  
    Luster: Vitreous - metallic  
    Diaphaneity: Opaque  
    Dichroism:
    (e):  
    (w:)  
    		 
    Ultra Violet
        Fluorescence:    		 None (One Sample Only Checked)
    Magnetism: Non-magnetic  
    Occurance:
  • Uranium-rich pegmatites
    		•   
    Associated
        Minerals:

    'Aeschynite', Autunite, Barite, Carnotite, Chalcopyrite, Francevillite, Hematite, Pyrite, 'Stilbite', Thomsonite, Torbernite, Uranospathite, Uranospinite, Zircon

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Davidite-(La)
    Localities:

    Very Rare

    Davidite-(La) Localities
    Notes:

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

    Images

    Billeroo, South Australia, Australia