The effect of tetrahedrite composition on its behaviour during leaching with ferric chloride-sodium chloride-hydrochloric acid solutions was investigated. This study used three natural samples of tetrahedrite with different compositions, which were analyzed by X-Ray diffraction and electron microprobe. The shrinking core model was applied to describe the leaching behaviour of the tetrahedrite samples and the results show that the iron content of the solid affects the leaching rate. In fact, increases in iron content increase the leaching rate of tetrahedrite and the results are interpreted in terms of the semiconductor theory. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.