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Evansite - Occurrence, Properties, and Distribution

Evansite is a secondary amorphous mineral occurring with allophane and limonite. This mineral was named after Brooke Evans, a British metallurgist from Birmingham, England who brought the first specimens from Hungary in 1855.

Properties of Evansite

The following are the key properties of Evansite:

  • Cell Data
    • Space Group: n.d
    • Z = n.d
  • Crystal Data
    • Amorphous
    • Point Group: n.d
    • Commonly as reniform or botryoidal coatings; spherulitic or stalactitic, to 0.6 m, may show a concentric structure.
    • X-ray powder pattern: Amorphous to X-rays.
  • Chemical Composition
    Elements Content 1 Content 2 Content 3
    H2O 39.95 41.27 42
    Al2O3 39.31 40.19 39.62
    P2O5 19.05 18.11 18.38
    insol. 1.41 - -
    Total 99.72 99.57 100
  • Optical Properties
    • Optical Class: Isotropic may show birefringence up to 0.02
    • n = 1.445–1.485.
  • Estimated Properties
    Electron density Bulk density (electron density) = 2.02 g/cm3
    note: Specific gravity of Evansite = 1.95 g/cm3
    Photoelectric PEEvansite = 1.11 barns/electron
    U = PEEvansite x ρElectron density = 2.23 barns/cm3
    Fermion index Fermion index = 0.0003
    Boson index = 0.9996


    Evansite is not radioactive.

How to Identify Evansite

Evansite can be colorless or blue, white, green and yellow. This mineral has transparent to translucent appearance with white streaks and vitreous luster. It exhibits non-fluorescent and non-magnetic properties. The conchoidal fractures developed in brittle materials are characterized by smooth curving surfaces. The mineral can be observed in various forms like stalactitic, reniform and botryoidal. The relative hardness of evansite ranges from 3.5 to 4, and its average density is 1.95 g/cm3.

Global Distribution

Evansite is distributed in the following places:

  • SIRK-Zeleznik (Vashegy), Slovakia
  • Gross-Tresny; Litošice
  • Alsô-Sajô, Romania
  • Rosia Montan˘a (Verespatak), Romania
  • Baia-de-Arie (Offenb´anya), Romania
  • Epernay, Marne, France
  • Campo Lameiro, Spain
  • Teis, near Vigo, Spain
  • Pontevedra Province
  • santa Cruz de Olarde, Barcelona Province
  • Richelle, near Vis´e, Belgium
  • Yoredale Rocks, near Macclesfield, Cheshire
  • Vatoinandry district, Madagascar
  • Berlin and other caves, Transvaal, South Africa
  • Zeehan and Dundas districts, Tasmania, Australia
  • Columbiana and Coalville, Shelby Co., Alabama
  • Wilson Springs, Garland Co., Arkansas
  • Goldburg, Custer Co., Idaho
  • Cueva de Cunday, Colombia
  • Cueva de Urtany and Cueva de Aguapiras Caves, Venezuela.

Occurrence of Evansite and Useful Mineral Association

Evansite occurs in a graphite deposit (Gross-Tresny, Czech Republic), graphitic gneiss (Vatoinandry district, Madagascar), coal seams (Alabama, USA) and coating in caves, the phosphate derived from guano. It is closely associated with limonite, allophane and variscite.


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