Yttrialite-(Y)

 IMA-GP
Thorium 55.2.1b.3
(Dana Classification Number)
(No Images) 8/C.01-40
(Strunz ID)

Property Data Remarks
Named for: Its Yttrium content.
Alternate
    Name(s):
  		•  
    Mineral Class:
    Silicates
      Sorosilicates, with [Si2O7]-6,
    without anions unfamiliar to tetrahedrons
        Thortveitite - Rowlandite-(Y) series
    		 
    Chemical
        Formula:    		 (Y,Th)2Si2O7  
    Chemical
        Composition:
    Oxygen: (O) 26.82%
    Silicon: (Si) 13.45%
    Thorium: (Th) 27.79%
    Yttrium: (Y) 31.94%
    		by weight
    Molecular
        Weight:    		 417.54 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.2448 × 1004 3.36 × 10-07 0.18 17.50

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Monoclinic - Prismatic
    Axial Ratios: a:b:c = 0.9106:1:0.6228
    Cell Dimensions: a = 7.34, b = 8.06, c = 5.02, Z = 2; beta = 108.5° V = 281.64 Den(Calc) = 4.92
    H-M Symbol: 2/m
    Space Group: P21/m
    X Ray Diffraction: By Intensity(I/Io): (1) () ()
    		 
    Habit:
  • Massive
  		•   
    Cleavage: None  
    Fracture: Conchoidal  
    Moh's
        Hardness:    		 5 - 5.5  
    Density: 4.58 grams/cm3
    Color: Olive-green  
    Streak:    
    Luster:    
    Diaphaneity:    
    Pleochroism:
    (x):
    (y:)
    (z:)
    		 
    Ultra Violet
        Fluorescence:    		 Non-fluorescent  
    Magnetism: Non-magnetic  
    Occurance:
  • Associated with gadolinite
  		•   
    Associated
        Minerals:

    'Allanite', Biotite, Chalcopyrite, 'Fergusonite', Fergusonite-(Y), Fluorite, 'Gadolinite', Hematite, 'Hornblende', Ilmenite, Lepidolite, Magnetite, Molybdenite, Polycrase-(Y), Pyrite, Quartz, Quartz var: Smoky Quartz, Rowlandite-(Y), Tengerite-(Y), Thalenite-(Y), Thorogummite, Uraninite, Xenotime-(Y), Yttrocrasite-(Y), Zircon

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

    		These are minerals known to be found with Yttrialite-(Y)
    Locations:

    Very rare

    Yttrialite-(Y) Locations

    The type locale is now inundated by Buchanan artifical Lake, along the Colorado River, Texas, U.S.A.
    Notes:

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

    Crystals are probably metamic.