Cervelleite Ag₄TeS, from three localities in Romania, substitution of Cu, and the occurrence of the associated phase, Ag₂Cu₂TeS

Abstract

Compositional and paragenetic data are reported for cervelleite, ideally Ag4TeS, from three new occurrences in Romania: from Upper Cretaceous skarn mineralisation at Babrevei¸ta Bihor, Northern Apuseni Mts. and Ocna de Fier, Banat, and from Neogene hydrothermal Au-vein mineralisation at Larga, Metalliferi Mts. Cervelleite from the two skarn occurrences contains significant amounts of Cu. Together with previously published compositional data, limited solid solution from Ag4TeS to approximately (Ag3.2Cu0.8)4TeS can be recognised. Closely associated with cervelleite in both skarn occurrences is an additional phase, Ag2Cu2TeS, which we believe is a possible new quaternary mineral in the Ag–Cu–Te–S system.