Natural djurleite with refined composition Cu 61.39 S 32 revealing disorder of some Cu sites.

A djurleite crystal was discovered from a natural sample originally labelled as chalcocite. The djurleite crystal under investigation has a refined composition of Cu 61.39 S 32 , thus revealing a Cu deficiency compared to the originally reported Cu 62 S 32 phase [Evans (1979). Z. Kristallogr. 150 , 299-320], where all atomic sites are reported to be fully occupied. In addition, the current refinement revealed a splitting of eight of the Cu sites into pairs.