Abstract: This work is concerned with the quantitative eleetron microprobe analysis of Pb-Bi sulfosalts, theiridentification and relation to other sulfosalts, and examination of their optical properties. The specimens are from theQueen Hill area of Zeehan, Tasmania.Electron microprobe analysis has confirmed the presence of two sulfosaits: a Bi-rich phase Pb3Bi5Ag2Sb S1 3)fand a Bi-poor phase (Pb9Bi8Ag Sb2S24) corresponding to gustavite and kobellite respectively.There are no characteristie differences in the optical properties of the two Pb-Bi phases. They are constantlyintergrovm with each other and frequently associated with pyrite, stannite, galena and bismuthinite. Texturally thesulfosalts form complex intergrowths with each other whieh are believed to be due to exsolution. They show replacement features of older minerals thus, paragenetically, are among the last phases to have crystallised.Analyses of some selected minerals are also carried out, namely galena, stannite, bismuthinite, tetrahedrite anda sulfoantimonide mineral which thought to be related t o freieslebenite.Examination of the minör element content of galena indicates that the ore field around Zeehan is of unusuallyhigh temperature, which is consistent with the field`s anomalous geochemiçal properties.