Polycrase-(Y)

 IMA-GP
Uranium
Thorium		 8.3.8.1
(Dana Classification Number)
(Images) 4/D.19-10
(Strunz ID)

Property Data Remarks
Named for: The Greek for "many" and "mixture", in reference to the large number of chemical elements in the formula
Alternate
    Name(s):
  		•  
    Mineral Class:
    Oxides
      Oxides with metal: (metal:oxygen = 1:2)
    (MO2 and related compounds)
        Polycrase-(Y) - Loranskite-(Y) series
    		 
    Chemical
        Formula:    		 (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6  
    Chemical
        Composition:
    Calcium: (Ca) 1.07%
    Cerium: (Ce) 3.76%
    Niobium: (Nb) 14.95%
    Oxygen: (O) 25.74%
    Tantalum: (Ta) 14.56%
    Thorium: (Th) 6.22%
    Titanium: (Ti) 15.41%
    Uranium: (U) 6.38%
    Yttrium: (Y) 11.92%
    		by weight
    Molecular
        Weight:    		 372.96 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.4211 × 1004 3.84 × 10-07 0.20 19.85

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Orthorhombic - Dipyramidal
    Axial Ratios: a: 0.3796
    b: 1
    c: 0.3549
    Cell Dimensions: a: 5.55 Å
    b: 14.62 Å
    c: 5.19 Å
    Z: 4
    V: 421.12 Å3
    DenCalc: 5.88
    H-M Symbol: 2/m 2/m 2/m
    Space Group: Pcan
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (0.):   Å
    (0.):   Å
    (0.):   Å
    		Polycrase-(Y)
    Crystal
    Habit:
  • Prismatic
  • Striated
  • Radial clusters
    		•   
    Cleavage: None  
    Fracture: Conchoidal  
    Moh's
        Hardness:    		 5 - 6  
    Density: 4.97 - 5.04 grams/cm3
    Color: Metalic black  
    Streak: Brown to Gray  
    Luster: Vitreous - Resinous  
    Diaphaneity: Subtranslucent to Opaque  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  
    		 
    Ultra Violet
        Fluorescence:    		 Non-fluorescent  
    Magnetism: Non-magnetic  
    Occurance:
  • Granitic pegmatites
    		•   
    Associated
        Minerals:

    Albite, 'Allanite', Allanite-(Ce), 'Apatite', Bastnäsite-(Ce), Bertrandite, Beryl, Biotite, Bismuthinite, Calcite, 'Chlorite Group', Euxenite-(Y), Fergusonite-(Y), Fluorapatite, Fluorite, 'Gadolinite', Gadolinite-(Y), 'Garnet Group', Hematite, Ilmenite, Magnetite, Microcline, Microlite, Molybdenite, Monazite-(Ce), Muscovite, Orthoclase, Pyrite, Pyrrhotite, Quartz, Quartz var: Smoky Quartz, Sphalerite, Tengerite-(Y), Uranothorite, 'Tourmaline Group', Uraninite, Xenotime-(Y), Zircon, Zircon var: Cyrtolite

    Mineral   -   > 69% of sites
    Mineral   -   > 46% of sites
    Mineral   -   > 23% of sites
    Minerals   -   Uranium & Thorium
    mineral links

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

    Rare

    Polycrase-(Y) Locations
    Notes:

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

    Crystals may be metamict.

    Polycrase-(Y) Images

    Specimen #1
    Outer Surface
    (001oa) (001ob) (001oc) (001od)

     
    Inner Surface
    (001ia) (001ib) (001ic) (001id)

     
    Yard Mine, Trout Creek Pass pegmatite district, Buena Vista, Chaffee Co., Colorado, U.S.A.

    Specimen Notes

    Occurrence - With the exception of (001ib) and (001ic), and pending further investigation, the images may be of Euxenite-(Y), which is chemically similar to Polycrase-(Y). The specimen requires more detailed analysis due to the chemical similarity of these two minerals.

    The specimen is a weathered pegmatite containing a varied mix of minerals. Identified are: Talc, Biotite, and Rose Quartz. Others are present, but are too badly weathered for positive identification.

    Crystals - The crystals of Polycrase-(Y) occur as pseudo-hexahedons in two clusters, image (00ib). Image (001ic) gives a higher magnification view of one of these clusters. Note that some of the crystals are only partially pseudo-hexahedrons.

    The crystals are quite small, and do not show the striations typical of Polycrase-(Y). The do show the pseudo-hexagonal habit of this mineral. Many also show thin, platy cleavages. A few have a more purely orthorhombic (box) shape with clipped corners, as if they failed to become completely pseudo-hexagonal. These are not believed to be Euxenite-(Y) as the angles are not the same as with that mineral, but this is difficult to confirm.

    Appearence - The specimen shows a heavily weathered surface (the 001oX series) as well as a less weathered inner surface. The weathered surface shows heavy crazing of the minerals as they are modified and broken up by the environment.

    Diaphaniety - The Polycrase-(Y) appears to be opaque.

    The vitreous black mineral, believed to be Euxenite(Y), is slightly translucent in very thin sections.

    Luster - The luster is vitreous, but is partially hidden by a very thin layer of what is believed to be lime from the talc, which surrounds the crystals. This lime film appears to cover most of the specimen.

     

      -  

     

    Specimen Physical Properties
    Size 7.37 cm 4.83 cm 3.30 cm
    Weight: 202.01 grams 22° C. 37% R/H
    g-Radiation Level:   cmp   msieverts background: 20 cpm