The silver-bearing phases in galena from Espeland are freibergite, unknown 'phase C' (Pb11Ag2Sb10S27), pyrargyrite, stephanite and hessite. The compositions of these phases were determined by electron microprobe. Freibergite is homogeneous in composition with an average 35 percent silver. The average calculated atomic proportions (Cu,Ag,Fe)12·2Sb4S12·4, deviate from the stoichiometric composition (Cu,Ag,Fe,Zn)12(SbAs)4S13 of tetrahedrite. It has been found that most of the silver present in the ore occurs in the silver phases and not in structural positions in the galena lattice.
Silver sulphosalts in galena from Espeland, Norway