Editorial Feature

Schallerite – Occurrence, Properties, and Distribution

Schallerite was discovered in 1924, in the Franklin Mining District of the USA. This mineral is named after Wakdemar Theodore Shaller, a mineralogist.

Properties of Schallerite

The key physical properties of Schallerite are as below:

  • Cell Data
    • Space group: P3m1
    • a = 13.43
    • c=14.31
    • Z = 2.
  • Crystal Data
    • Hexagonal
    • Point group: n.d
    • Crystals – structure of Schallerite crystals is hemimorphic, with steep pyramids that are terminated by dull f0001g and f0001g pedions. As slightly rectangular aggregates that resemble augen; also granular to massive.
    • X-ray powder pattern: 1.688 (100), 2.673 (60), 1.511 (60), 2.466 (50), 2.022 (50), 3.55 (40), 1.975 (40).
  • Chemical Composition
    Elements Content 1 Content 2 Content 3
    SiO2 32.0 31.51 31.27
    TiO2 - 0.03 -
    Al2O3 - 0.01 -
    Fe2O3 2.6 - -
    As2O3 12.81 11.41 12.87
    FeO - 0.14 -
    MnO 42.5 48.90 49.22
    ZnO 1.6 - -
    MgO 2.3 0.06 -
    CaO - 0.02 -
    Cl 0.0 0.11 -
    H2O 6.82 [6.73] 6.64
  • Optical Properties
    • Optical class: Uniaxial
    • ω = 1.681–1.704
    • ε = 1.643–1.679.
  • Estimated Properties
    Electron density Bulk density (electron density) = 3.24 g/cm3
    note: Specific gravity of Schallerite = 3.37 g/cm3
    Photoelectric PESchallerite = 16.95 barns/electron
    U = PESchallerite x ρelectron density = 54.89 barns/cm3
    Fermion index Fermion index = 0.007
    Boson index = 0.992
    Radioactivity
     
    GRapi = 0 (Gamma Ray American Petroleum Institute Units)
    Schallerite is not radioactive.

How to Identify Schallerite

Schallerite appears in the form of light-to-reddish brown mineral on the fields. It is in the form of translucent, uniformly undistinguishable crystals that form large masses. This mineral has a vitreous, waxy luster with a light brown streak. The density of these crystals is 3.37 g/cm3, hardness ranges from 4.5-5 (close to Apatite). Schallerite is non-magnetic and non-flouorescent.

Global Distribution

Schallerite is widely distributed in the following locations:

  • USA- from Betts Manganese Mines, Hampshire, Massachusetts and Franklin Mining District, New Jersey
  • Sweden –from Persberg District, Varmland
  • Romania – from Suceava District
  • Austria – from Kals Valley, East Tyrol.

Occurrence of Schallerite and Useful Mineral Association

Schallerite is commonly associated with ores such as willemite-franklinite, rhodonite. It occurs in a metamorphosed form of stratiform zinc deposit. It is also associated with calcite, tephroite, spessartine, rhodochrosite and pyroxmangite.

References

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