Johannite

 IMA-GP
Uranium 31.8.2.1
(Dana Classification Number)
(Images) 6/D.21-10
(Strunz ID)

Property Data Remarks
Named for:  
Alternate
    Name(s):
  • Gilpinite (Ferroan variety of Johannite)
  • Uranvitriol
  • Péligotite
    		•   
    Mineral Class:
    Sulfates,Chromates,Molybdates and Tungstates
      Uranylsulfates [UO2]+2 - [SO4]-2
        Johannite - Schröckingerite series
    		 
    Chemical
        Formula:    		 Cu(UO2)2(SO4)2(OH)2 · 8H2O  
    Chemical
        Composition:
    Copper: (Cu) 6.53%
    Hydrogen: (H) 1.86%
    Oxygen: (O) 36.14%
    Sulfur: (S) 6.59%
    Uranium: (U) 48.88%
    		by weight
    Molecular
        Weight:    		 973.87 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    8.7501 × 1004 2.36 × 10-06 7.51 751.31

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Triclinic - Pinacoidal
    Axial Ratios: a: 0.9301
    b: 1
    c: 0.7132
    Cell Dimensions: a: 8.92 Å
    b: 9.59 Å
    c: 6.84 Å
    Z: 1
    a: 110°
    b: 111.983°
    g: 100.3°
    V: 501.63 Å3
    DenCalc: 3.22
    H-M Symbol: -1
    Space Group: P-1
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 7.73 Å
    (0.9): 6.16 Å
    (0.8): 3.41 Å
    		Johannite
    Crystal
    Habit:
  • Druse
  • Reniform
  • Massive
    		•   
    Cleavage:
    [001]  
    [010]  
    [100] Good
    		 
    Fracture:    
    Moh's
        Hardness:    		 2 - 2.5  
    Density: 3.3 - 3.5 grams/cm3
    Color: Grass green  
    Streak: Light green  
    Luster: Vitreous  
    Diaphaneity: Transparent to translucent  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  
    		 
    Ultra Violet
        Fluorescence:    		 Non-fluorescent  
    Magnetism: Non-magnetic  
    Occurance:
  		•  
    Associated
        Minerals:

    Aragonite, Autunite, Azurite, Barite, Becquerelite, Bismuth, Bornite, Brochantite, Calcite, Cerussite, Chalcanthite, Chalcocite, Chalcopyrite, Coffinite, Copper, Covellite, Cuprosklodowskite, Dewindtite, Dolomite, Fluorite, Galena, Goethite, Gypsum, Hematite, Kaolinite, Malachite, Marcasite, Metatorbernite, Phosphuranylite, 'Psilomelane', Pyrite, Schoepite, Siderite, Sklodowskite, Sodium-Zippeite, Sphalerite, Torbernite, Uraninite, Uranophane, Uranopilite, Zeunerite, Zippeite

    Mineral   -   > 74% of sites
    Mineral   -   > 49% of sites
    Mineral   -   > 26% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Johannite
    Localities:

    Rare

    Johannite Localities
    Notes:

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

    Crystals are probably metamict.

    Johannite Images

    Specimen #1
    (001a) (001b) (001c)
    (Uranopilite-001a) (Uranopilite-001b) (Uranopilite-001c) (Uranopilite-001d)

     
    (Uranopilite-001e) (Uranopilite-001f)
    Apex Mine, Lander Co., Nevada, U.S.A.


    Specimen Notes

    Occurrence - Both Johannite and Uranopilite occur in proximity to each other, often either growing on each other, or totally intergrown. In the upper right corner of image Uranopilite-001a, the Uranopilite can be seen to have grown on the Johannite, and later overgrown by the Johanite, so the clusters of Uranopilite became encased in the Johannite.

    The chemical composition of Johannite and Uranopilite differ primarily in that the Johannite includes copper in its composition. Otherwise, they are very much alike, chemically. This likely accounts for their co-occurrance on the specimen. The Uranopilite was likely deposited when the mother liqure was depleated of, or lacking, copper.

    The host rock is limestone that is partially metamorphosed into marble, as can be seen in images 001c and Uranopilite-001f. The limestone/marble has a definite grain to it, as the fracture with the grain is quite smooth, while that across the grain if very uneven. In places, the conversion to marble is quite obviously incomplete, with whiteish lime between grains of Aragonite. This can best be seen in image 001c.

    Crystals - The Johannite occurs as both a crust of massive, intergrown crystals that lose their identity (images Uranopilite-001a Uranopilite-001b), and as radial clusters of acicular crystals (Images 001a, 001b, Uranopilite-001d and Uranopilite-001e). These clusters are nearly two-dimentional due to their growth in a crack in the host rock. The individual crystals are under 0.3 mm in length, though some,particularly in the massive crust, can be considerably larger.

    In some areas, as seen in image 001c, the crystal clusters occur as many very small clusters over a wide area. It is likely that the massive crust first began as this form of deposit.

    The radial clusters occur as both well coordinated and somewhat jumbled structures. Images 001a and 001b show both radial cluster structures. In image 001b, some of the radial clusters form sunbursts due to the tightness of the crack within which they formed, and the coordination of their crystals to each other.

    Diaphaneity - The Johannite varies from nearly transparent in the radial clusters, to trancluscent in the massive crust. This is likely due to the crust being more rapidly deposited than the slower growth of the clusters.

    Luster - The Johannite is vitreous (glassy) in luster, both the crystal clusters and the massively intergrown crust layer.

    Specimen Physical Properties
    Size:      
    Weight: x grams    
    g-Radiation Level:   cmp   msieverts background: 20 cpm
           

     

    Specimen #2
    (002a) (002b)
    Happy Jack Mine, Copper Point, White Canyon, White Canyon District, San Juan Co., Utah, U.S.A.


    Specimen Notes

    Occurrence -  

     

      -  

     

    Specimen Physical Properties
    Size:      
    Weight: x grams    
    g-Radiation Level:   cmp   msieverts background: 20 cpm