Editorial Feature

Akatoreite – Occurrence, Properties, and Distribution

Akatoreite was named after the place it was initially discovered - Akatore Creek, New Zealand.

Properties of Akatoreite

The following are the key properties of akatoreite:

  • Cell Data
    • Space group: P1
    • a = 8.337(2)
    • b = 10.367(2)
    • c = 7.629(1)
    • α = 104:46(1)°
    • β = 93:81(2)°
    • γ = 104:18(1)°
    • Z =1

  • Crystal Data
    • Triclinic
    • Point group: 1
    • Rarely as sheaves, to 1cm, of radiating prisms, elongated and striated || [100]
    • Fibrous, fine granular, massive
    • Twinning: On {021}
    • Twin axis ⊥ {021}, lamellar in thin section
    • X-ray powder pattern: 4.665 (100), 3.310 (90), 2.214 (80), 9.681 (60), 3.466 (50), 3.063 (50), 2.866 (50)

  • Chemical Composition
    Elements Content 1 Content 2
    MnO 47.7 44.2
    SiO2 36.4 36.9
    Al2O3 8.3 6.2
    H2O 6.21 [10.7]
    FeO 1.0 0.9
    MgO 0.3 0.8
    CaO 0.2 0.2
    TiO2 0.03 0.1
    Total 100.14 [100.0]

  • Optical Properties
    • Optical class: Biaxial (+)
    • Pleochroism: X = colorless; Y = pale yellow; Z = light canary-yellow
    • Orientation: X ^ {010} = 58°; Y^{010} = 30°
    • α = 1.698(1); β =1.704(1); γ = 1.720(1)
    • 2V(meas.) = 65.5°

  • Estimated Properties
    Electron density Bulk density (electron density) = 3.38 g/cm3
    note: Specific gravity of akatoreite = 3.48 g/cm3.
    Photoelectric PEAkatoreite = 10.46 barns/electron
    U = PEAkatoreite x ρ electron density = 35.35 barns/cm3
    Fermion index Fermion index = 0.0084
    Boson index = 0.9915
    Radioactivity Akatoreite is not radioactive

How to Identify Akatoreite

Akatoreite can be identified in the field by its color variations, such as orange and brown. Its transparent form has {010} perfect, {021} good cleavage. This mineral has a vitreous luster, with yellow-white streak.

The density of akatoreite is 3.48 g/cm3, with a hardness of 6 - approximate to orthoclase.

Global Distribution

Akatoreite is distributed in the following places:

  • New Zealand - 3km south of Akatore Creek, east Otago, South Island
  • Sweden - From Norberg

Occurrence of Akatoreite and Useful Mineral Association

Akatoreite occurs in a manganiferous metachert and carbonate lens in schists, and in manganiferous potassium-rich felsic metavolcanics.

It is often associated with minerals such as rhodochrosite, apatite, pyroxmangite, spessartine, quartz, rhodonite, tinzenite, todorokite, alabandite, ganophyllite, rhodochrosite, pyrolusite, and haubnerite.

References

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