Kobellite: Properties and Occurrences

Kobellite [Pb22Cu4(Bi, Sb)30S69] is a gray, fibrous, metallic mineral. It is also a sulfide mineral consisting of antimony, bismuth, and lead. The mineral can be found in ores and deposits of Hvena, Sweden; Ouray, Colorado; and Wake County, North Carolina, US. The mineral was named after Wolfgang Franz von Kobell (1803–1882), a German mineralogist.

General

  • Category: Sulfide minerals
  • Formula: [Pb22Cu4(Bi,Sb)30S69]
  • Crystal system: Orthorhombic
  • Crystal class: Dipyramidal (mmm)
  • H-M symbol: (2/m 2/m 2/m).

Fig: Kobellite

Physical Properties

It is a member of the izoklakeite – berryite series with silver and iron substituting in the copper site and a varying ratio of bismuth, antimony, and lead. It crystallizes with monoclinic pyramidal crystals.

  • Colour: Blackish lead-gray to steel-gray
  • Luster: Metallic
  • Hardness: 2½ – 3
  • Specific Gravity: 6.334
  • Crystal System: Orthorhombic.
  • Transparency: Opaque
  • Streak: Black
  • Cleavage: Distinct/Good good on 010
  • Density: 6.334 g/cm3 (Measured) and 6.51 g/cm3 (Calculated).

Occurrence: A high-temperature hydrothermal mineral.

Locations include Hvena, Sweden; Ouray, Colorado; and Wake County, North Carolina, USA.

Association: Cobaltite, arsenopyrite, chalcopyrite (Vena mines, Sweden); bismuthinite, jamesonite, tetrahedrite (Raleigh, North Carolina, USA).

 

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