AM_Tetradymite_1 Formula: Bi2 Te2 S Name: Tetradymite Unit cell: 10.33 10.33 10.33 24.17 24.17 24.17 , V=162.41 Space group: R-3 (148)

Harker D , Zeitschrift fur Kristallographie , 89 (1934) p.175-181, The crystal structure of the mineral tetradymite, Bi2Te2S, Locality: Hungary