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University of Silesia in Katowice

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Institute of Earth Sciences

How to distinguish two similar, Ag-bearing minerals from each other: investigation of djurleite from Poland

13.05.2021 - 15:11 update 13.05.2021 - 15:15
Editors: lukaszmalarzewski

The chalcocite group minerals are widely distributed among different hydrothermally affected rocks, the oxidized zone of copper sulfide deposits, or may be even crystalline from supersaturated volcanic gases. Some of the chalcocite group minerals form the main Cu orebodies. Djurleite (Cu31S16) is a rare member of the chalcocite group, with a very complex structure. The physical and chemical similarities between all members of the group make them almost unidentifiable by macroscopic and microscopic methods. In this study, Ag-bearing djurleite from the Kupferschiefer deposits, Lower Silesia, Poland, is characterized by EMPA (Electron Microprobe Analyses), XRD (X-Ray Diffraction), and Raman spectroscopy. Djurleite from the investigated site has the following general, average chemical formula: Cu30.86Ag0.1Fe0.04S16. The Ag content is up to 0.55 wt.%, while Fe is up to 0.19 wt.%. The presence of djurleite confirms a low-temperature (~90 °C), hydrothermal origin of the Cu-Ag deposit in Kupferschiefer, which is consistent with previously studies. Moreover, the authors believe that Ag-rich djurleite may often be mistaken for Ag-rich chalcocite, which used to be one of the main Ag-bearing minerals in the orebody from the Cu-Ag deposit in the Fore-Sudetic Monocline. More details in:

Szopa, K.; Krzykawski, T.; Banasik, K.; Król, P.; Skreczko, S.; Mounteanou, S.A.; Koziarska, M. EMPA, XRD, and Raman Characterization of Ag-Bearing Djurleite from the Lubin Mine, Lower Silesia, Poland. Minerals 2021, 11, 454. https://doi.org/10.3390/min11050454

Sample of studied djurleite (previously identified as chalcocite), from the mineralogical collection of the Earth Sciences Museum, University of Silesia in Katowice, Poland.
Sample of studied djurleite (previously identified as chalcocite), from the mineralogical collection of the Earth Sciences Museum, University of Silesia in Katowice, Poland.
Djurleite (Dj) associated with bornite (Brn), anhydrite (Anh) and pyrite (Py). Reflected light.
Djurleite (Dj) associated with bornite (Brn), anhydrite (Anh) and pyrite (Py). Reflected light.
(a) XRD pattern of the investigated djurleite compared with both calculated models (by the Rietveld method) and chalcocite (a basic standard). (b) List of all peaks from the characterized sample and a typical djurleite (ICDD, PDF4+ standard (#04-007-1283 reference code).
(a) XRD pattern of the investigated djurleite compared with both calculated models (by the Rietveld method) and chalcocite (a basic standard). (b) List of all peaks from the characterized sample and a typical djurleite (ICDD, PDF4+ standard (#04-007-1283 reference code).
Raman shifts of all minerals from the investigate sample from the Lubin mine, Poland. A basic chalcocite standard is added for comparison.
Raman shifts of all minerals from the investigate sample from the Lubin mine, Poland. A basic chalcocite standard is added for comparison.
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