Ardaite - Occurrence, Properties, and Distribution

Topics Covered

Introduction to Ardaite
Properties of Ardaite
How to Identify Ardaite
Global Distribution
Occurrence of Ardaite and Useful Mineral Association
References

Introduction to Ardaite

Chemical Formula – Pb19Sb13S35Cl7

Ardaite is a rare sulfosalt mineral, discovered in 1980 from Madjarovo, Arda River, Bulgaria.

It was named after its place of discovery.

Properties of Ardaite

The following are the key properties of Ardaite:

  • Cell Data
    • Space Group: n.d
    • a = 21.09
    • b = 22.11
    • c = 8.05
    • β = 103.02°
    • Z = 2

 

  • Crystal Data
    • Monoclinic
    • Point Group: n.d
    • As aggregates of acicular crystals, to 2µm, as isolated inclusions in sulfides and sulfosalts
    • X-ray Powder Pattern: 3.43 (100), 2.83 (80), 3.13 (40), 1.90 (30), 4.24 (20), 3.90 (20), 2.36 (20)

 

  • Chemical Composition
    Elements Content 1 Content 2 Content 3 Content 4
    Pb 56.50 57.94 57.14 59.37
    Sb 22.48 21.44 22.97 20.94
    S 15.56 15.44 16.29 15.62
    Cl 3.78 4.39 3.60 4.06
    Ag 0.04 - - -
    Fe - 0.31 - -
    Total 98.36 99.52 100.00 100.00

 

  • Optical Properties
    • Pleochroism: Distinct
    • Anisotropism: Distinct

 

  • Estimated Properties
    Electron density Bulk density (electron density) = 5.27 g/cm3
    note: Specific gravity of Ardaite = 6.26 g/cm3
    Photoelectric PEArdaite = 1123.48 barns/electron
    U = PEArdaite x ρElectron density = 5920.32 barns/cm3
    Fermion index Fermion index = 0.12
    Boson index = 0.88
    Radioactivity
    Ardaite is not radioactive

How to Identify Ardaite

Ardaite is an opaque, green-gray mineral that is formed as aggregates, or needle-like crystals visible only with microscopes.

It has metallic luster, and a relative hardness ranging between 2.5 and 3.

Global Distribution

Ardaite is distributed in the following places:

  • Madjarovo, eastern Rhodope Mountains, Bulgaria
  • Dressfall mine, Gruvasen, Bergslagen metallic province, Sweden

Occurrence of Ardaite and Useful Mineral Association

Ardaite occurs rarely in polymetallic ore deposits.

The minerals that are closely associated with ardaite include graphite, nisbite, arsenopyrite, antimony, silver, pyrargyrite, stannite, scheelite, magnetite, chalcopyrite, pyrrhotite, sphalerite, anglesite, argentian tetrahedrite, pyrostilpnite, chlorian semseyite, chlorian robinsonite, and galena.

References

 

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