Thorbastnäsite

 IMA-A
Thorium 16b.1.2.1
(Dana Classification Number)
(No Images) 5/E.10-10
(Strunz ID)

Property Data Remarks
Named for: Its relationship to Bastnäsite (named for Bastnäs Mine, Riddarhyttan, Vastmanland, Sweden), and its Thorium content
Alternate
    Name(s):
  • Thorbastnaesite
    		•   
    Mineral Class: Nitrates, Carbonates and Borates -
    - Thorbastnäsite series    		  
    Chemical
        Formula:    		 Th(Ca,Ce)(CO3)2F2 · 3H2O  
    Chemical
        Composition:
    Calcium: (Ca) 5.90%
    Carbon: (C) 4.72%
    Cerium: (Ce) 6.88%
    Fluorine: (F) 7.46%
    Hydrogen: (H) 1.19%
    Oxygen: (O) 28.28%
    Thorium: (Th) 45.57%
    		by weight
    Molecular
        Weight:    		 509.19 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    2.0416 × 1004 5.52 × 10-07 0.29 28.56

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Hexagonal - Ditrigonal Dipyramidal
    Axial Ratios: a:c = 1:1.38912
    Cell Dimensions: a = 6.99, c = 9.71, Z = 2; V = 410.87 Den(Calc)= 4.12
    H-M Symbol: -6 m2
    Space Group: P-62c
    X Ray Diffraction: By Intensity(I/Io): 2.03(1) 2.85(1) 3.54(0.8)
    		 
    Habit:
  		•  
    Cleavage:
    [001]
    [010]
    [100]
    		 
    Fracture:    
    Moh's
        Hardness:    		 4 - 4.5  
    Density: 4.04 grams/cm3
    Color: Brown  
    Streak:    
    Luster: Vitreous - Greasy  
    Diaphaneity: Translucent  
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:
    Short Wave:
    		 
    Magnetism: Non-magnetic  
    Occurance:
  		•  
    Associated
        Minerals:

    Aegirine, Albite, Analcime, Barite, Calcite, Cryolite, Eudialyte, Fluorapatite, Fluorite, Galena, Hematite, Magnetite, 'Mangan-neptunite', Microcline, Natrolite, Nepheline, Pectolite, Polylithionite, Pyrochlore, Pyrrhotite, Quartz, Rhodochrosite, Serandite, Sodalite, Sphalerite, Thorite, Villiaumite, Zircon

    Mineral   -   all sites
    Mineral   -   75% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Thorbastnäsite
    Locations:

    Very rare

    Thorbastnasite Locations
    Notes:

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

    Crystals are probably metamic.