Algodonite - Occurrence, Properties, and Distribution

Topics Covered

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

Introduction to Algodonite

Chemical Formula – Ni++C31H32N4

Algodonite is a gray-white metallic, copper arsenide mineral, crystallizing in a hexogonal pattern. The mineral was first discovered from the Algodones silver mine in Coquimbo, Chile in 1857.

It has a Mohs hardness of 4, and a specific gravity of 8.38 to 8.72.

Properties of Algodonite

The following are the key properties of Algodonite:

  • Cell Data
    • Space Group: P63/mmc
    • a = 2.600
    • c = 4.228
    • Z = 2


  • Crystal Data
    • Hexagonal
    • Point Group: 6/m 2/m 2/m
    • As incrustations of minute highly distorted crystals; commonly massive and granular
    • X-ray powder pattern: 1.989 (100), 2.11 (40), 2.25 (20), 1.299 (20), 1.194 (20), 1.110 (20), 0.837 (20)


  • Chemical Composition
    Elements Content 1 Content 2 Content 3
    Cu 83.11 83.53 83.58
    As 16.44 16.55 16.42
    Ag Trace - -
    Total 99.55 100.08 100.00


  • Optical Properties
    • Opaque
    • Color: Steel-gray to silver-white, tarnishes dull on exposure; in polished section, bright cream-white.
    • Luster: Bright metallic
    • Anisotropism: Weak


  • Estimated Properties
    Electron density Bulk density (electron density) = 8.33 g/cm3
    Note: Specific gravity of Algodonite = 9.18 g/cm3
    Photoelectric PEOligoclase = 50.32 barns/electron
    U = PEOligoclase x ρElectron density = 419.22 barns/cm3
    Fermion index Fermion index = 0
    Boson index = 1
    Algodonite is not radioactive

How to Identify Algodonite

Algodonite can be identified in silver-white or steel-gray color forms. This mineral is opaque and non-fluorescent in nature. It has metallic lustre and nonmagnetic properties. Sub-conchoidal fractures are developed in brittle materials, having semi-curving surfaces. It forms massive granular crystals, commonly observed in granite or other igneous rock.

It has an average density of 8.55 g/cm3, and a relative hardness of 4.

Global Distribution

Algodonite is distributed in the following places:

  • Algodones silver mine, near Coquimbo, Chile
  • Cerro de las Seguas, Rancagua, O’Higgins Province, Chile
  • Corocoro, Bolivia
  • Kokito II mine, Neuqu´en Province, Argentina
  • Keweenaw Co. Michigan, USA
  • Mohawk, Pewabic, Seneca, Ahmeek, and Champion mines, USA
  • Houghton Co. Painesdale
  • Baraga Co. Colorado
  • Cashin mine, Montrose Co.
  • Langban, Varmland, Sweden
  • Roua copper mines, about 50km north of Nice, Alpes-Maritimes, France
  • Tsumeb, Namibia
  • Talmessi mine, 35km west of Anarak, Iran

Occurrence of Algodonite and Useful Mineral Association

Algodonite is uncommon in hydrothermal deposits, and is closely associated with other copper arsenides, koutekite, domeykite, and silver.



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