Augelite – Occurrence, Properties, and Distribution

Augelite has been named after the Greek word for luster, for its pearly appearance on the cleavage.

Properties of Augelite

The following are the key properties of augelite:

  • Cell Data
    • Space group: C2/m
    • a = 13.124(6)
    • b = 7.988(5)
    • c = 5.066(3)
    • β = 112.25(2)°
    • Z = 4.
  • Crystal Data
    • Monoclinic
    • Point group: 2/m
    • As thick tabular crystals, {001}, to 13 cm, may be prismatic, even acicular || [001], showing many forms, dominantly {110}, {001}, {201}. {111}, with {110} striated || [001]; may be massive
    • X-ray powder pattern: 3.344 (100), 3.517 (55), 4.007 (30), 4.706 (25), 4.673 (25), 3.490 (25), 1.869 (18).
  • Chemical Composition
    Elements Content 1 Content 2 Content 3
    P2O5 35.04 34.68 35.50
    SiO2 - 0.07 -
    TiO2 - 0.08 -
    Al2O3 49.15 50.33 50.99
    Fe2O3 0.89 - -
    MnO 0.31 - -
    CaO 1.09 - -
    H2O 12.85 - 13.51
    Total 99.33 - 100.00
  • Optical Properties
    • Transparent
    • Color: colorless to white, maybe yellowish to pale rose, greenish, colorless in transmitted light
    • Streak: white
    • Luster: vitreous, pearly on perfect {110} cleavage
    • Optical Class: Biaxial (+)
    • Dispersion: r>v, moderate
    • α = 1.5736; β = 1.5759; γ = 1.5877
    • 2V(meas) = 50°49’; 2V(calc) = 47°56’
    • Orientation: X = b; Y ∧ c = –56° ; Z ∧ c = 34°.
  • Estimated Properties
    Electron density Bulk density (electron density) = 2.70 g/cm3
    note: Specific gravity of augelite = 2.70 g/cm3
    Photoelectric PEAugelite = 1.56 barns/electron
    U = PEAugelite x ρ electron density = 4.20 barns/cm3
    Fermion index Fermion index = 0.0002711168
    Boson index = 0.99972
    Radioactivity Augelite is not radioactive.

How to Identify Augelite

Augelite appears as a colorless to white to yellowish to pale rose, greenish and appears colorless in transmitted light.

Global Distribution

Augelite is found in the following locations:-

  • Sweden – from Vastana mone, near Nasum, Skane, Halsjoberg, Varmland.
  • Uganda – from Mbale.
  • Rwanda – from the Buranga pegmatite, near Gatumba.
  • USA – from Champion mine, White Mountains, Mono Co, California; New Hampshire, at the Palmero number 1 mine, near North Groton, G.E.Smith mine Newport, Sullivan Co; in the Hugo and Ingersoll mines, near Keystone, Pennington Co; South Dakota, in the White Picacho district, Maricopa and Yavapai Co Arizona.
  • Canada – from the Big Fish River, Yukon Territory.
  • Bolivia – from Socavon mine, San Jose and Itos mines, Oruro; at Llallagua, Machacamarca, Tatasi and Portugalete, Potosi.
  • Australia – from Mt.Perry, Bundaberg in Queensland.

Occurrence of Augelite and Useful Mineral Association

Augelite is formed by the hydrogen metamorphism of phosphate-bearing rocks in peraluminous sediments and in some high-temperature hydrothermal ore deposits.

It is often associated with minerals such as attakolite, svanbergite, lazulite, hematite, trolleite, berlinite, rutile, pyrophyllite, barite, arsenopyrite, stannite, pyrite, andorite, cassiterite and zinkenite.

References

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