The Neves Corvo mine lies in the Iberian Pyrite Belt and contains different types of polymetallic ores mined for copper (the main ore mineral is chalcopyrite) and tin (the main ore mineral is cassiterite). Other tin sulphides such as stannite and different forms of chalcostannate) occur in various amounts depending on ore types. The tin mineralogy in both ore samples and concentrator products was analyzed at microscopic scales to better understand the complexity and diversity of the different ore types at the Neves Corvo deposit. Optical and electron microscopy was supplemented by electron and ion microprobe analyses to determine the location and concentration of selected trace elements such as indium in the minerals from the different Neves Corvo ore types. Analytical refinements were first carried out particularly the spectral interference encountered in both EPMA and SIMS analyses between tin and indium. It was shown in this study that indium is usually linked to stannite and stannoidite at the Neves Corvo deposit. Mawsonite, which has a chemical formula similar to stannoidite but a different crystal structure, is free of indium, whereas stannoidite contains indium. Sn-119 Mossbauer spectroscopy was proven useful in the tin mineral quantification within these ores where at least two different tin states are often found. (C) 2003 Elsevier Ltd. All rights reserved.