Tritomite-(Ce)

 IMA-GP
Thorium (minor) 54.2.5.1
(Dana Classification Number)
(No Images) 8/B.33-40
(Strunz ID)

Property Data Remarks
Named for: The Greek for "three" and "to cut," in allusion to the trihedral cavities left in their matrix by the crystals
Alternate
    Name(s):
  		•  
    Mineral Class:
    Silicates
      Nesosilicates, with
    with anions unfamiliar to tetrahedrons,
    with beryllium and boron
        Melanocerite-(Ce) - Tritomite-(Ce) series
    		 
    Chemical
        Formula:    		 (Ce,La,Ca,Y,Th)5(Si,B)3(O,OH,F)13  
    Chemical
        Composition:
    Boron: (B) 0.69%
    Calcium: (Ca) 10.17%
    Cerium: (Ce) 26.68%
    Fluorine: (F) 4.82%
    Hydrogen: (H) 0.38%
    Lanthanum: (La) 17.63%
    Oxygen: (O) 22.34%
    Silicon: (Si) 8.91%
    Yttrium: (Y) 3.95%
    Thorium: (Th) 4.42%
    		by weight
    Molecular
        Weight:    		 787.79 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.979 × 1003 5.35 × 10-08 0.03 2.81

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Hexagonal - Dipyramidal
    Axial Ratios: a:c = 1:0.73582
    Cell Dimensions: a = 9.35, c = 6.88, Z = 2; V = 520.89 Den(Calc) = 5.02
    H-M Symbol: 6/m
    Space Group: P63/m
    X Ray Diffraction: By Intensity(I/Io): 2.81(1) 1.84(0.4) 3.44(0.4)
    		 
    Habit:
  • Pyramidal
  		•   
    Cleavage: None  
    Fracture: Brittle - Conchoidal  
    Moh's
        Hardness:    		 5.5  
    Density: 4.2 grams/cm3
    Color: Dark brown  
    Streak:    
    Luster: Vitreous - Resinous  
    Diaphaneity: Translucent to Sub-opaque  
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:
    Short Wave:
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Nepheline Syenite
  		•   
    Associated
        Minerals:

    Aegirine, 'Aegirine-augite', Albite, Analcime, Arfvedsonite, Biotite, Britholite-(Ce), Catapleiite, Chalcopyrite, Chevkinite-(Ce), Eudialyte, Fluorite, Galena, Homilite, Leucophanite, Låvenite, Magnetite, Microcline, Molybdenite, 'Mosandrite', Natrolite, Nepheline, Pectolite, Prehnite, Riebeckite, Rosenbuschite, Sodalite, Sphalerite, Zircon

    Mineral   -   > 80% of sites
    Mineral   -   > 60% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Tritomite-(Ce)
    Locations:

    Very rare

    Tritomite-(Ce) Locations
    Notes:

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

    Crystals may be metamic.