Tristramite

 IMA-A 1982-037
Uranium 40.4.7.6
(Dana Classification Number)
(No Images) 7/C.29-50
(Strunz ID)

Property Data Remarks
Named for: After the medieval figure associated with the Arthurian legend.
Alternate
    Name(s):
  		•  
    Mineral Class:
    Phosphates, Arsenates and Vanadates
      Water-bearing phosphates without unfamiliar anions, cations of medium and big size: Fe, Mn, Zn, Mg and Ca, (NH4)+
        Rhabdophane group
    		 
    Chemical
        Formula:    		 (Ca,U+4,Fe+3)(PO4,SO4) · 2H2O  
    Chemical
        Composition:
    Calcium: (Ca) 10.35%
    Hydrogen: (H) 1.74%
    Iron: (Fe) 2.40%
    Oxygen: (O) 41.32%
    Phosphorus: (P) 10.00%
    Sulfur: (S) 3.45%
    Uranium: (U) 30.74%
    		by weight
    Molecular
        Weight:    		 232.32 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    5.5021 × 1004 1.49 × 10-06 0.81 81.16

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Hexagonal - Trapezohedral
    Axial Ratios: a:c = 1:0.92897
    Cell Dimensions: a = 6.913, c = 6.422, Z = 3; V = 265.79 Den(Calc) = 4.35
    H-M Symbol: 6 2 2
    Space Group: P6222
    X Ray Diffraction: By Intensity(I/Io): 2.83(1) 2.99(1) 2.14(0.5)
    		 
    Habit:
  		•  
    Cleavage: None  
    Fracture:    
    Moh's
        Hardness:    		 3 - 4  
    Density: 3.8 - 4.2 grams/cm3
    Color: Pale yellow, Green-yellow  
    Streak:    
    Luster: Greasy  
    Diaphaneity: Translucent  
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:
    Short Wave:
    		 
    Magnetism: Non-magnetic  
    Occurance:
  		•  
    Associated
        Minerals:

    Arsenopyrite, Azurite, Cassiterite, Chalcocite, Chalcopyrite, Clinoclase, Connellite, Copper, Cuprite, Fluorite, Goethite, Malachite, Opal, Pyrite, Quartz (var: Amethyst, Citrine, Smoky Quartz), Torbernite, Uraninite, Zippeite

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Tristramite
    Locations:

    Very rare

    Tristramite Locations
    Notes:

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

    Crystals are probably metamic.