Schmitterite

 IMA-A 1967-045
Uranium 34.1.6.1
(Dana Classification Number)
(Images) 4/K.03-10
(Strunz ID)

Property Data Remarks
Named for: Eduardo Schmitter Villada, Professor of Mineralogy and petrography at the National University of Mexico.
Alternate
    Name(s):
  • Schmitterit
  • Schmitterita
    		•   
    Mineral Class:
    Oxides
      Sulfides, selenides, tellurides with [XO3]-2 groups and related structures
        Schmitterite - Moctezumite series
    		 
    Chemical
        Formula:    		 (UO2)TeO3  
    Chemical
        Composition:
    Oxygen: (O) 17.95%
    Tellurium: (Te) 28.63%
    Uranium: (U) 53.41%
    		by weight
    Molecular
        Weight:    		 445.63 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    9.5612 × 1004 2.58 × 10-06 1.24 123.61

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Orthorhombic - Dipyramidal
    Axial Ratios: a: 0.779
    b: 1
    c: 0.532
    Cell Dimensions: a: 7.86 Å
    b: 10.089 Å
    c: 5.368 Å
    Z: 4
    V: 425.68 Å3
    DenCalc: 6.95
    H-M Symbol: 2/m 2/m 2/m
    Space Group: Pmab
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 3.682 Å
    (0.9): 3.099 Å
    (0.9): 5.35 Å
    		 
    Habit:
  • Small granular crystals
  • Massive
  • Crystal clusters
  • 'Glaze'
    		•   
    Cleavage:
    [001]  
    [010]  
    [100] Good
    		 
    Fracture:    
    Moh's
        Hardness:    		 1  
    Density: 6.8 - 6.9 grams/cm3
    Color: Colorless to Yellowish  
    Streak: White  
    Luster: Pearly  
    Diaphaneity: Transparent to Translucent  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  
    		 
    Ultra Violet
        Fluorescence:
    Long Wave:  
    Short Wave:  
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • A secondary mineral in the oxidized portions of a telluride-bearing deposit
    		•   
    Associated
        Minerals:

    Bambollaite, Barite, Burckhardtite, Calcite, Carlfriesite, Chalcomenite, Cliffordite, Cuzticite, Denningite, Emmonsite, Eztlite, Goethite, Gold, Jarosite, Kuranakhite, Mackayite, Moctezumite, Mroseite, Paratellurite, Poughite, Quartz, Rodalquilarite, Sonoraite, Spiroffite, Tellurite, Tellurium, Zemannite

    Mineral   -   All of the sites
    Mineral   -   > 60% of sites
    Mineral   -   > 40% of sites
    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Schmitterite
    Locations:

    Very rare

    Schmitterite Locations
    Notes:

    Extremely radioactive: a- and b-particles, g-rays.

    Crystals are probably metamict.

    Schmitterite Images

    Specimen #1
    (001a) (001b) (001c) (001d)
    (001e) (001f) (001g)
    Moctezuma mine, Moctezuma, Mun. de Moctezuma, Sonora, Mexico


    Specimen Notes

    Occurance - The Schmitterite occurs on what appears to be a substrate of a mixture of silicate rock dust cemented by calcium carbonate, probably Aragonite, as well as impure Aragonite. The host rock appears to be a silicate mineral. The Schmitterite occurs in a band that encloses an area, as would be expected it it was deposited around the perifery of a small puddle that was slowly evaporating. A second, more tenuous, band can be seen in places, most easily in the upper left corner of image 001a.

    The 'periferal deposition' structure of the Schmitterite, together with what appear to be the initial buds of stalagmites that appear in the lower left quadrent and lower right corner of 001a, indicate that these images of the specimen are its in-ground top.

    Crystals - The crystals are all too small to be visable under a microscope at 30X. It is suspected that they are aligned to each other, giving the Schmitterite its silky to pearly luster.

    A deposit of what appears to be powdery calcium carbonate (talc?) can be seen in the lower right quadrents of images 001a and 001e, and in the left half of 001g. This deposit can be easily differentiated from the Schmitterite by its dull, powdery appearence.

    Luster - The luster of the Schmitterite varies from silky to pearly. It is this luster that indicates the presence of microcrystals. It is also this luster that makes the Schmitterite easily differentiated from the calcium carbonate deposit near by.

    Emmonsite - Emmonsite is a Tellurite, Fe23+(SeO3)3 · 2H2O, that is related to Schmitterite. It rarely forms crystals, though several can be seen in about the center of image 001c.

    Specimens of Emmonsite from the Moctezuma mine are reported to be in close association with Schmitterite, Cuzticite, Sonoraite and other tellurite minerals. This mineral is reported to be no longer abbundant from this mine. (Data on this mineral from Dana, 1997).

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