Grayite

 IMA-GP
Thorium 40.4.7.4
(Dana Classification Number)
(No Images) 7/C.29-60
(Strunz ID)

Property Data Remarks
Named for: Anton Gray, mining engineer, U. K. Atomic Energy Authority
Alternate
    Name(s):
  		•  
    Mineral Class:
    Phosphates, Arsenates and Vanadates
      Water-bearing phosphates with familiar anions and cations of medium and large size:
    Fe, Mn, Zn, Mg and Ca, (NH4)+
        Rhabdophane group
    		 
    Chemical
        Formula:    		 (Th,Pb,Ca)PO4 · H2O  
    Chemical
        Composition:
    Calcium: (Ca) 1.26%
    Hydrogen: (H) 0.63%
    Lead: (Pb) 19.52%
    Oxygen: (O) 25.13%
    Phosphorus: (P) 9.73%
    Thorium: (U) 43.73%
    		by weight
    Molecular
        Weight:    		 318.38 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.9591 × 1004 5.29 × 10-07 0.27 2.65

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Hexagonal - Trapezohedral
    Axial Ratios: a: 1
    c: 0.91936
    Cell Dimensions: a: 6.957 Å
    c: 6.396 Å
    Z: 2
    V: 268.09 Å3
    DenCalc: 3.94
    H-M Symbol: 6 2 2
    Space Group: P6222
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 3.04 Å
    (0.8): 2.14 Å
    (0.8): 2.82 Å
    		 
    Habit:
  • Cryptocrystalline
  • Aggregates
    		•   
    Cleavage: None  
    Fracture: Conchoidal  
    Moh's
        Hardness:    		 3 - 4  
    Density: 3.7 - 4.3 grams/cm3
    Color: Pale yellow, reddish brown  
    Streak:    
    Luster: Resinous  
    Diaphaneity: Translucent  
    Dichroism:
    (e):  
    (w:)  
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:  
    Short Wave:  
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Lithium pegmatites
    		•   
    Associated
        Minerals:

    Aegirine, Albite, Almandine, Anatase, Barite, Bastnäsite-(Ce), Biotite, Brookite, Calcite, Cancrinite, 'Columbite', Diopside, Fluorapatite, Fluorite, Hastingsite, Hematite, Ilmenite, Kaolinite, Magnetite, Microcline, Microlite, Monazite-(Ce), Muscovite, Natrolite, Nepheline, Phenakite, Pyrite, Pyrochlore, Quartz, Rutile, Schorl, Siderite, Thorite, Thorogummite, Titanite, Wollastonite, Xenotime-(Y), Zinnwaldite, Zircon

    Mineral   -   All of the sites
    Mineral   -   > 75% of sites
    Mineral   -   > 50% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Grayite
    Localities:

    Rare

    Grayite Localities
    Notes:

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

    Crystals are probably metamict.