Editorial Feature

Chalcopyrite - Occurrence, Properties, and Distribution

Chalcopyrite is a copper iron sulfide mineral, having a tetragonal crystal system. It was named after the Greek word chalkos, meaning copper, and pyrites, meaning strike fire.

Properties of Chalcopyrite

The following are the key properties of Chalcopyrite:

Elements Content 1 Content 2
Cu 35.03 34.63
S 34.96 34.94
Fe 31.00 30.43
Total 100.99 100.00

  • Cell Data
    • Space Group: I42d
    • a = 5.281
    • c = 10.401
    • Z = 4

  • Crystal Data
    • Tetragonal
    • Point Group: 42m
    • Equant, tetrahedral-shaped crystals, may be modified by scalenohedral faces, to as large as 10cm. Sphenoidal faces {112} typically large, dull in luster, and striated k [110]; {112} faces are small and bright. Commonly massive, compact; can be botryoidal
    • Twinning: Twin plane {112}, composition surface commonly {112}; twin plane {012}; also by rotation about [001] with composition plane {110}, producing penetration twins
    • X-ray Powder Pattern: 3.038 (100), 1.8570 (35), 1.5927 (27), 1.8697 (22), 1.5753 (14), 2.644 (5), 1.2025 (5)

  • Chemical Composition

  • Optical Properties
    • Anisotropism: Weak

  • Estimated Properties
    Electron density Bulk density (electron density) = 3.98 g/cm3
    note: Specific gravity of Chalcopyrite = 4.20 g/cm3
    Photoelectric PEChalcopyrite = 26.59 barns/electron
    U = PEChalcopyrite x ρElectron density = 105.88 barns/cm3
    Fermion index Fermion index = 0.0090
    Boson index = 0.9909
    Radioactivity
    Chalcopyrite is not radioactive

How to Identify Chalcopyrite

Chalcopyrite can be identified in the field by its honey-yellow or brass-yellow variations, with a greenish-black streak, and metallic luster. It has an indistinct cleavage, and becomes magnetic after heating. It is non-fluorescent, with opaque properties. Its fractures are brittle, as shown by non-metallic minerals and glasses. It can be formed as euhedral crystals, with striated lines on the crystal face.

The average density of chalcopyrite is 4.19 g/cm3, and its hardness is 3.5.

Global Distribution

Chalcopyrite is distributed in the following places:

  • Copper mines of Arizona
  • Groundhog mine, Vanadium, Grant Co. New Mexico
  • Rossie lead mines, St. Lawrence Co. New York
  • Chester Co. Pennsylvania
  • Joplin, Jasper Co. Missouri
  • Cananea, Sonora, Mexico
  • Creek mine, near Timmins, Huaron
  • Bansk´a Stiavnica (Schemnitz), Slovakia
  • Horn´i Slavkov (Schlaggenwald), Czech Republic
  • Freiberg, Saxony
  • Dillenburg, Hesse
  • Georg mine, near Horhausen, Westerwald
  • A number of mines in North Rhine-Westphalia, Germany
  • Vinsknoes, Karmoen, Norway
  • Ani and Arakawa mines, Akita Prefecture, Japan
  • Nababiep mine, Cape Province, South Africa

Occurrence of Chalcopyrite and Useful Mineral Association

Chalcopyrite occurs as a primary mineral in hydrothermal veins, stockworks, disseminations, and massive replacements, or as an ex-solution product in mafic igneous rocks. It can also be found as a sedimentary origin, controlled by redox conditions.

Minerals such as pyrite, tetrahedrite, galena, sphalerite, and some of the copper sulfides, are closely associated with chalcopyrite.

References

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