A rare indium-bearing mineral (Zn-In-Cu-Fe sulphide) from the Stara Kamienica Schist Belt (Sudetes, SW Poland)

A rare indium-bearing mineral from the stratiform Czerniawa Zdrój-Krobica Sn deposit in the Sudetes (NE part of the Bohemian Massif) has been recognized in the qualitative-quantitative chemical composition studies of sulphide-cassiterite samples by electron microprobe (EMPA). This indium-bearing mineral occurs in the form of separate hipautomorphic microscopic grains (diameter 5-20 μm) and as intergrowths and disseminations in chalcopyrite. Observations indicate that this phase crystallized with the main generation of chalcopyrite, sphalerite and also with a younger generation of cassiterite in the mineral succession. The chemical composition of this mineral is as follows: S – 29.38-30.77 wt.%, Zn – 29.76-34.02 wt.%, In – 17.52-19.40 wt.%, Cu – 9.05-10.75 wt.%, Fe – 7.76-8.7 wt.% and Sn – 0.03-0.1 wt.%. Its calculated chemical formula is: (Zn2.09In0.67Cu0.65Fe0.64Cd0.02)Σ4.07S4.0 and it is characterized by enrichment of Zn with simultaneous depletion in Cu and Sn relative to the ideal chemical composition of sakuraiite – the most similar mineral in terms of chemical composition. In the light of our new data, it should be considered as a yet unnamed Zn-In-Cu-Fe sulphide mineral. In addition, coexisting sulphide minerals – chalcopyrite (max. 1580 ppm of In) and sphalerite (max. 1640 ppm of In) were identified as indium carriers.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).