Copper in Coloradoite, HgTe: Actual State or Analytical Artifact?

Chemical and structural data of two Cu-rich coloradoite crystals from Kalgoorlie, Australia, are reported. Two grains with simple stoichiometries, i.e., Hg1 – xCuxTe with x ~0.30, and ~0.22, were characterized by single-crystal X-ray diffraction and electron-probe microanalysis. In the absence of single-crystal data it might be tempting to hypothesize that the presence of large amounts of other elements can induce some ordering leading to distinct mineral species. However, structural analyses show that all of the phases are cubic and crystallize in the space group $$F\overline 4 3m$$ . On the basis of information gained from the chemical and structural characterization it can be concluded that there is a complete solid solution between coloradoite and a possible, still unknown, Cu-coloradoite in nature.