Triangulite

 IMA-A 1981-056
Uranium 40.2a.34.1
(Dana Classification Number)
(No Images) 7/E.05-20
(Strunz ID)

Property Data Remarks
Named for: The triangular habit of its crystals
Alternate
    Name(s):
  		•  
    Mineral Class: Phosphates, Arsenates, Vanadates -
    - Ranunculite - Moreauite series    		  
    Chemical
        Formula:    		 Al3(UO2)4(PO4)4(OH)5 · 5H2O  
    Chemical
        Composition:
    Aluminum: (Al) 4.72%
    Hydrogen: (H) 0.88%
    Oxygen: (O) 31.70%
    Phosphorus: (P) 7.22%
    Uranium: (U) 55.48%
    		by weight
    Molecular
        Weight:    		 1,716.05 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    9.9314 × 1004 2.68 × 10-06 1.37 136.63

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Triclinic
    Axial Ratios: a:b:c = 0.9839:1:1.0037
    Cell Dimensions: a = 10.39, b = 10.56, c = 10.6, Z = 1; alpha = 116.4°, beta = 107.8°, gamma = 113.4° V = 910.28 Den(Calc) = 3.13
    H-M Symbol:
    Space Group: P1, P1-
    X Ray Diffraction: By Intensity(I/Io): 7.8(1) 3.87(0.8) 3.15(0.7)
    		 
    Habit:
  • Triangular Crystals
  • Rhombohedral Crystals
  • Aggregates
  		•   
    Cleavage:
    [???] Perfect
    		 
    Fracture:    
    Moh's
        Hardness:    		 2 - 3  
    Density: 3.7 grams/cm3
    Color: Bright yellow  
    Streak: Light yellow  
    Luster:    
    Diaphaneity:    
    Pleochroism: Pale greenish yellow
    (x):
    (y:) Pale greenish yellow
    (z:) Bright yellow
    		 
    Ultra Violet
        Fluorescence:    		 Non-fluorescent  
    Magnetism: Non-magnetic  
    Occurance:
  • Complex pegmatite
  		•   
    Associated
        Minerals:

    Althupite, Amblygonite, Beryl, Columbite', Dumontite, Eylettersite, Furongite, Kamitugaite, Lusungite, Meta-Autunite, Metavanmeersscheite, Montebrasite, 'Moreauite', Mundite, Phosphuranylite, Phuralumite, Plumbomicrolite, Quartz, Ranunculite, Rutherfordine, Saléeite, Studtite, Threadgoldite, Upalite, Uraninite, Vanmeersscheite

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Triangulite
    Locations:

    Extremely rare

    Triangulite Locations
    Notes:

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

    Crystals are probably metamic.