Thornasite

 IMA-A 1985-050
Thorium 72.1.2.1
(Dana Classification Number)
(No Images) 8/D.20-10
(Strunz ID)

Property Data Remarks
Named for: Its composition; Thorium, Sodium (Natrium), and Silicon
Alternate
    Name(s):
  		•  
    Mineral Class:
    Silicates
      Unclassified silicates, with
    mostly cations of large size Na, K, Ca, Sr, Pb
        Thornasite series
    		 
    Chemical
        Formula:    		 Na12Th3[Si8O19]4 · 18H2O
    or:
    (Na,K)Th,Si11(O,OH,F,Cl)25 · 8H2O    		  
    Chemical
        Composition:
    Hydrogen: (H) 1.06%
    Oxygen: (O) 44.09%
    Silicon: (Si) 26.35%
    Sodium: (Na) 8.09%
    Thorium: (Th) 20.41%
    		by weight
    Molecular
        Weight:    		 3,410.96 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    9.143 × 1003 2.47 × 10-07 0.14 13.75

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Trigonal - Hexagonal Scalenohedral
    Axial Ratios: a:c = 1:0.59264
    Cell Dimensions: a = 29.124, c = 17.2602, Z = 6; V = 12,678.81 Den(Calc) = 2.68
    H-M Symbol: -3 2/m
    Space Group: R-3c
    X Ray Diffraction: By Intensity(I/Io): 7.27(1) 4.17(0.7) 8.17(0.3)
    		 
    Habit:
  • Microscopic Crystals
  • Anhedral Grains
    		•   
    Cleavage: None  
    Fracture:    
    Moh's
        Hardness:    		    
    Density: 2.62 grams/cm3
    Color: Colourless, pale green  
    Streak: White  
    Luster: Vitreous - Waxy  
    Diaphaneity: Transparent to Translucent  
    Dichroism:
    (e:) Colorless
    (w:)
    		 
    Ultra Violet
        Fluorescence:
    Long Wave: Bright green
    Short Wave: Bright green
    		 
    Magnetism: Non-magnetic  
    Occurance:
  		•  
    Associated
        Minerals:

    Acanthite, Aegirine, Albite, Almandine, 'Amphibole Group', Analcime, Anatase, Anglesite, Antimony, Aragonite, Arsenopyrite, Astrophyllite, Barite, Beryl, Beryllonite, Biotite, Bismuth, Brockite, Calcite, Carbonate-fluorapatite, Celestine, Cerite-(Ce), Cerussite, Chalcopyrite, 'Chlorite Group', Corundum, Cryolite, Diopside, Dolomite, Dravite, Ekanite, Epidote, Fluorapatite, Fluorite, Galena, 'Gmelinite Series', Goethite, Graphite, Grossular, Gypsum, Halite, Hematite, Hemimorphite, Hydrozincite, Ilmenite, Jarosite, Kaolinite, Lead, Löllingite, Magnesite, Magnetite, Marcasite, Mckelveyite-(Y), Microcline, Millerite, Mimetite, Molybdenite, Monazite-(Ce), Montmorillonite, Muscovite, Natrite, Natrolite, Natron, Natrophosphate, Neptunite, Nickeline, Opal, Orthoclase, Phillipsite-K, Phlogopite, Phosinaite-(Ce), Pyrite, Pyrochlore, Pyrrhotite, Quartz, Rhodochrosite, Richterite, Riebeckite, Rutile, Scheelite, Schorl, Siderite, Sodalite, Spessartine, Sphalerite, Steacyite, Steenstrupine-(Ce), Strontianite, Sulphur, Synchysite-(Ce), Tetrahedrite, Thorbastnasite, Thorite, Thornasite, Thorogummite, Titanite, Tugtupite, Vermiculite, Vesuvianite, Wollastonite, Wulfenite, Xenotime-(Y), Zeophyllite, Zircon

    Mineral   -   both of the sites
    Mineral   -   one of the sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are a few of the minerals known to be found with Thornasite
    Locations:

    Extremely rare

    Thornasite Locations
    Notes:

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

    Crystals are probably metamic.