Dear Clemente, I think I am not alone who would be interested in your experiences with the induction generator. Have you observed correlation between the appropriate frequency and the mineral studied? What is the frequency that you use for biotite and amphibole? Cheers, Attila Dr. Attila Demeny Laboratory for Geochemical Research Hungarian Academy of Sciences Budapest, Budaorsi ut 45, H-1112, Hungary tel/fax: 36-1-319-3145 e-mail: [log in to unmask]