The origin of copiapite from chlorite pyritic schist (Wieściszowice, Lower Silesia, Poland) in the light of Mössbauer analysis

Abstract

This work presents the results of the analysis of copiapite, formed from weathering and oxidation of pyrite in pyritic schist from Wieściszowice, Lower Silesia (Poland). The pure phase of copiapite was found in secondary minerals after pyrite and identified by optical microscopy, XRD and Mössbauer spectroscopy. In the analyzed copiapite major cations appear to be Fe 2+ and Fe 3+ . Some Fe 3+ is substituted by other cations, mainly Al 3+ . Al 3+ probably comes from leaching of chlorite from which hydrated sulphates of iron, mainly szomolnokite, form followed by hydrated sulphates fibroferrite, which is replaced by copiapite.