Tin-polymetallic vein type deposits are one of the major source of metal producers in the Circum Pacific Belt. This type of
deposit is of great importance for the modem electronics and medical industries because of their high content of rare
metals (especially indium and bismuth). We have studied two representatives, Tosham of India (Cu-In-Bi-Sn-W-Ag-Au),
and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), using proton and electron microprobes in order to delineate the
distribution of medical/high-tech rare metals. The electron microprobe study showed that major indium carrier in such
type of deposit are roquesite (CulnSZ), sphalerite, stannite and a Cu-Zn-Fe-In-Sn-S mineral; and that indium is
incorporated in sulfides by coupled substitution like Cu + In = 2(Zn + Fe). The proton microprobe showed that indium at
trace levels is also present in chalcopyrite and pyrite. In addition, zinc, copper, arsenic, antimony, selenium, tin, and
bismuth are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and
bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are higher in Mount Pleasant ore, but silver
is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is genetically related
to S-type magma, while the Mount Pleasant deposit is related to A-type granite. Tosham ore contains zinc-bearing biotites
that coexist with chalcopyrite in ore bodies but Mount Pleasant ore lacks such biotite. We propose that the difference in
elemental abundance between the two deposits are caused by the different character of source magma and different
mineral associations of the ore body.