Agardite-(Y) – Occurrence, Properties, and Distribution

Topics Covered

Introduction to Agardite-(Y)
Properties of Agardite-(Y)
How to Identify Agardite-(Y)
Global Distribution
Occurrence of Agardite-(Y) and Useful Mineral Association
References

Introduction to Agardite-(Y)

Chemical Formula - (Y, Ca) Cu6 (AsO4)3(OH)6 •3H2O

Agardite-(Y) was named after Jules Agard, a geologist at the Bureau de Recherches Geologiques et Minieres in Orleans, France. This mineral belongs to the mixite group.

Properties of Agardite-(Y)

The following are the key properties of agardite-(Y):

  • Cell Data
    • Space group: P63/m
    • a = 13.583(2)
    • c = 5.895(2)
    • Z = 2

 

  • Crystal Data
    • Hexagonal
    • Point group: 6/m
    • Acicular, prismatic
    • Elongated along [0001], a few mm long
    • X-ray powder pattern:11.73 (10), 2.938 (8), 2.451 (8), 4.43 (7), 3.54 (7), 2.692 (6), 2.558 (6)

 

  • Chemical Composition
    Elements Content 1 Content 2
    CuO 45.35 44.50
    As2O5 31.50 32.28
    H2O 11.35 [10.47]
    Y2O3 7.5 4.08
    PbO - 4.60
    La2O3 - 2.68
    CaO 2.60 0.65
    RE2O3 1.2
    Nd2O3 - 1.15
    Gd2O3 - 0.62
    Ce2O3 - 0.44
    Pr2O3 - 0.21
    Al2O3 - 0.20
    SiO2 - 0.15
    Sm2O3 - 0.08
    Bi2O3 - 0.04
    P2O5 - 0.03
    Total 99.50 [102.18]

 

  • Optical Properties
    • Semi-transparent
    • Optical class: Uniaxial (+)
    • ω = 1.701–1.723
    • ε = 1.777–1.815

 

  • Estimated Properties
    Electron density Bulk density (electron density) = 3.49 g/cm3
    note: Specific gravity of Agardite-(Y) = 3.69 g/cm3
    Photoelectric PEAgardite-(Y) = 39.59 barns/electron
    U = PEAgardite-(Y) x ρ electron density = 264.47 barns/cm3
    Fermion index Fermion index = 0.00017
    Boson index = 0.99982
    Radioactivity
    Agardite-(Y) is not radioactive

How to Identify Agardite-(Y)

Agardite-(Y) can be identified in the field by its color variations, such as blue-green, and blue. Its translucent form has a vitreous luster, with a greenish-white streak.

The density of agardite-(Y) is 3.66 to 3.72 g/cm3, with a hardness of 3 to 4 - between calcite and fluorite. The mineral is acicular, with spherical and rounded aggregates, and bundled tabular aggregates similar to rose petals.

Global Distribution

Agardite-(Y) is distributed in the following places:

  • Spain - From the Luisito mine, Anora, C´ordoba Province
  • Germany - At Schneeberg, Saxony; in the Clara mine, near Oberwolfach, Black Forest
  • Italy - On Sardinia, from the Santa Lucia and Sa Duchessa mines, near Iglesias
  • France - From the Cap Garonne mine, near le Pradet, Var, and Chessy, near Lyon, Rhone
  • UK - In Wheal Alfred, Cornwall, England; At the Gwaithyrafon mine, Cwmsymlog, Wales
  • Japan - At Hayasi, Setoda, Ikuchi Island, Hiroshima Prefecture
  • Australia - From Broken Hill, New South Wales
  • USA – From the Tintic district, Juab Co. Utah; in the Mohawk mine, Clark Mountains, San Bernardino Co. California; and at Granite Gap, San Simon district, Hidalgo Co. New Mexico
  • Morocco - In the Bou Skour mine, Djebel Sarhro
  • Congo - At Mutoshi, Katanga Province

Occurrence of Agardite-(Y) and Useful Mineral Association

Agardite-(Y) occurs in the oxidation zone of some copper deposits.

It is often associated with minerals such as azurite, chrysocolla, malachite, cuprite, copper, quartz, and mimetite.

References

 

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