Betafite

 IMA-A (GP) 1977-SUB
Uranium 8.2.3.1
(Dana Classification Number)
(Images) 4C.16-10
(Strunz ID)

Property Data Remarks
Named for: Betafo, Malagasy Republic, Madagascar, its type location
Alternate
    Name(s):
  • Blomstrandite
  • Mendeleyevite
  • Samiresite
  • Tantalbetafite
  • Titanbetafite
  
Mineral Class:
Oxides
  Oxides with metal:
(metal:oxygen = 2:3)
(M2O3 and related compounds)
    Pyrochlore group
      Betafite series
[with Ti > (Nb,Ta)]
 
Chemical
    Formula:		 (Ca, U)2(Ti, Nb, Ta)2O6OH  
Chemical
    Composition:
Aluminum: (Al) 0.65%
Calcium: (Ca) 1.93%
Iron: (Fe) 1.35%
Hydrogen: (H) 0.73%
Niobium: (Nb) 20.14%
Oxygen: (O) 26.98%
Uranium: (U) 17.20%
Tantalum: (Ta) 21.79%
Titanium: (Ti) 9.23%
by weight
Molecular
    Weight:		 415.12 daltons (amu)
Specific
    Radioactivity:

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

Specific Activity Dose Rate
Becquerels Curies  milliRems 
hour		  microSieverts 
hour
3.0791 × 1004 8.32 × 10-07 0.43 43.08

Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
Crystalography:
System: Isometric - Hexoctahedral
Axial Ratios: a:  
b:  
c:  
Cell Dimensions: a: 10.31 Å
Z: 10
V: 1,095.91 Å3
DenCalc: 6.29
H-M Symbol: 4/m -3 2/m
Space Group: Fd3m
X-Ray Diffraction:
  By Intensity ( I/Io )		 (1): 2.96 Å
(0.45): 1.814 Å
(0.4): 1.546 Å
Betafite
Crystals
Habit:
  • Octahedral and dodecahedral crystals are the common form. Often modified by other isometric forms, and/or flattened when two opposing faces dominate the crystal.
  • Encrustations
  • Massive - Granular (commonly observed in igneous rock)
  • Large crystals are common
    		•   
    Cleavage: None  
    Fracture: Conchoidal  
    Moh's
        Hardness:    		 4 - 5.5  
    Density: 3.7 - 5.0
        (extreme variation due to variable composition)    		 grams/cm3
    Color: Brown, brown-yellow, black, brownish green, yellow, or greenish black
    Crystals/specimens are often coated with a yellow or green earthy coating    		  
    Streak: Yellowish white to Yellow to Brown  
    Luster: Earthy to waxy to metallic
        Sometimes vitreous when translucent    		  
    Diaphaniety: Translucent to Opaque  
    Pleochroism: None  
    Ultra Violet
        Fluorescence:    		 None  
    Magnetism: Non-magnetic  
    Occurance:
  • Pegmatites
    		•   
    Associated
        Minerals:

    Aegirine, Albite, Allanite-(Ce), Analcime, 'Apatite', Augite, Biotite, Calcite, Cancrinite, 'Chlorite', Corundum, Diopside, Epidote, Euxenite-(Y), Fluorapatite, Fluorite, Galena, Gypsum, Hematite, 'Hornblende', Ilmenite, Magnetite, Microcline, Molybdenite, Muscovite, Nepheline, Perovskite, Pyrite, Pyrochlore, Pyrrhotite, Quartz, 'Scapolite', Sodalite, Sphalerite, Spinel, Thorite var: Uranothorite, Titanite, 'Tourmaline Group', Uraninite, Zircon

    Mineral   -   > 67% of sites
    Mineral   -   > 50% of sites
    Mineral   -   > 25% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Betafite
    Localities:

    Somewhat rare

    Betafite Localities
    Notes:

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

    Crystals are probably metamic.

    Some crystals can be quite large. The largest crystal found weighed 104 kg.

    Betafite Images

     

    Specimen #1

    Specimen #2

    		  
      Betafo, Malagasy Republic, Madagascar
    (part of original find)    		  

    Specimen #3
    Bancroft, Ontario, Canada
    (on Apatite crystal)