'Freibergite Subgroup' (not an IMA approved species)
Formula:
(Ag6,[Ag6]4+)(Cu4C22+)Sb4S12S0-1
Comments:
According to Zhou (1994), argentian tetrahedrite is relatively abundant at Dexing, but freibergite does not occur. This makes the earlier report by Yan (1978) questionable, who only lists freibergite.