Dervillite - Occurrence, Properties, and Distribution

Dervillite is a monoclinic-prismatic brownish-black mineral, containing sulfur, silver, and arsenic.

It was named after Dr. Henri Dervile of Strasbourg University in Strasbourg, France, who observed the original specimen.

Properties of Dervillite

The following are the key properties of Dervillite:

  • Cell Data
    • Space Group: P2/a
    • a = 6.833
    • b = 12.932
    • c = 9.638
    • β = 99°33'
    • Z = [8]

  • Crystal Data
    • Monoclinic
    • Point Group: 2/m
    • Minute crystals, to 0.3mm
    • X-ray Powder Pattern: 3.075 (10), 3.019 (8), 2.843 (5), 3.251 (3), 2.659 (3), 3.170 (2), 2.742 (2)

  • Chemical Composition
    Elements Content 1 Content 2
    Ag 61.39 60.81
    As 19.03 21.11
    S 18.06 18.08
    Total 98.48 100.00

  • Optical Properties
    • Anisotropism: Moderate

  • Estimated Properties
    Electron density Bulk density (electron density) = 2.52 g/cm3
    note: Specific gravity of Dervillite = 2.81 g/cm3
    Photoelectric PEDervillite = 170.89 barns/electron
    U = PEDervillite x ρElectron density = 430.40 barns/cm3
    Fermion index Fermion index = 0.0013
    Boson index = 0.9986
    Radioactivity
    Dervillite is not radioactive

How to Identify Dervillite

Dervillite can be identified by its brownish-black color, having metallic luster, black streak, and good cleavage.

It is opaque, with a relative hardness ranging from 1 to 1.5.

Global Distribution

Dervillite is mainly observed in museum specimens from the Gabe-Gottes mine, Rauenthal, near Sainte-Marie-aux-Mines, Haut-Rhin, France.

Occurrence of Dervillite and Useful Mineral Association

Dervillite occurs in a Co–Ni–Fe–As deposit.

Quartz, calcite, proustite, safflorite, rammelsbergite, and arsenic are the minerals that are closely associated with dervillite.

References

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