 There is a complete solid solution series between high digenite and berzelianite Cu2−xSe (x~0.12).High digenite is stable above 73 °C, with space group Fmm and unit cell parameters a=5.57 Å and Z=1 for formula Cu7.2−xS4.High digenite is isostructural with bornite Cu5FeS4.