Vyacheslavite

 IMA-A 1983-017
Uranium 40.4.8.3
(Dana Classification Number)
(No Images) 7/D.43-10
(Strunz ID)

Property Data Remarks
Named for: Vyacheslav Gavilovich Melkov (1911-), Russian mineralogist
Alternate
    Name(s):
  		•  
    Mineral Class: Phosphates, Arsenates, Vanadates -
    - Vyacheslavite - Lermontovite series    		  
    Chemical
        Formula:    		 U+4(PO4)(OH) · 2.5-5H2O  
    Chemical
        Composition:
    Hydrogen: (H) 1.53%
    Oxygen: (O) 30.38%
    Phosphorus: (P) 7.84%
    Uranium: (U) 60.25%
    		by weight
    Molecular
        Weight:    		 395.05 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    1.07854 × 1005 2.91 × 10-06 1.48 147.89

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Orthorhombic
    Axial Ratios: a:b:c = 0.7648:1:1.3604
    Cell Dimensions: a = 6.96, b = 9.1, c = 12.38, Z = 6; V = 784.10 Den(Calc) = 5.02
    H-M Symbol:
    Space Group: Cmcm, Cmc21, C2cm
    X Ray Diffraction: By Intensity(I/Io): 6.19(1) 2.69(0.7) 4.56(0.6)
    		 
    Habit:
  • Spherical
  • Aggregates
  • Tabular
    		•   
    Cleavage:
    [001]
    [010] Distinct
    [100]
    		 
    Fracture:    
    Moh's
        Hardness:    		    
    Density: 4.9 - 5.01 grams/cm3
    Color: Dark green  
    Streak: Green  
    Luster:    
    Diaphaneity:    
    Pleochroism:
    (x): Weak green
    (y:) Weak green
    (z:) Weak green
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:
    Short Wave:
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Found on quartz crystals associated with octahedral pyrite
  		•   
    Associated
        Minerals:

    Chalcocite, Covellite, Ningyoite, Pyrite, Quartz, Sphalerite

    Mineral   -   65% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Vyacheslavite
    Locations:

    Very rare

    Vyacheslavite Locations
    Notes:

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

    Crystals are probably metamic.