Mineral Database (Saesneg yn unig)

Mineral Database (Saesneg yn unig)
Mineralogy of Wales

Kobellite

Crystal System: Orthorhombic
Formula: Pb22Cu4(Bi,Sb)30S69
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Distribution: Rare
Chemical Composition: Lead copper bismuth antimony sulphide
Method(s) of Verification: Parys Mountain - EMPA (Sivaprakash, 1977).
Chemical Group:
  • Sulphosalts
Geological Context:
  • Hydrothermal : volcanogenic massive sulphides
Introduction: kobellite is occasionally found as a minor mineral in hydrothermal ore deposits with other sulphosalts and sulphides. There are only a few localities worldwide. As with many of the sulphosalt minerals, kobellite is not easy to identify without resorting to detailed analytical techniques.
Occurrence in Wales: the first and only Welsh occurrence of kobellite at Parys Mountain was recorded by Sivaprakash (1977) and was the first record of the mineral in the UK.
Key Localities:
  • Parys Mountain, Anglesey: kobellite forms as fine-grained intergrowths 5-20 µm in size, associated with native bismuth, bismuthinite, galenobismutite and bournonite, in contact rims around chalcopyrite, galena and tetrahedrite group minerals. It was also present as inclusions in sphalerite and as a cement to framboidal pyrite (Pointon & Ixer, 1980).
References:
  • Pointon, C.R. & Ixer, R.A., 1980 Parys Mountain mineral deposit, Anglesey, Wales: geology and ore mineralogy.  Transactions of the Institution of Mining and Metallurgy (Section B: Applied earth science), 89, B143-B155.
  • Sivaprakash, C., 1977 Geochemistry of some sulphides and sulphosalts from Parys Mountain, Anglesey.  Unpublished M.Phil. thesis, University of Aston in Birmingham.