AMPH-IMA97: a hypercard program to determine the name of an amphibole fromelectron microprobe and wet chemical analyses

In 1997, the International Mineralogical Association (IMA) revised the amph ibole naming scheme making it necessary to amend the previous EMP-AMPH Maci ntosh program to the new rules. The ANIPH-IMA97 program allows single input or automatic input of as many amphibole analyses as are available followin g a set input format. There are three options for calculation scheme of amp hibole analysis: (1) complete chemical analyses can be calculated to 24(O, OH, F, Cl); (2) analyses with determined FeO and Fe2O3 but without H2O can be calculated to 23(O) and (3) electron microprobe analyses with only total Fe determined and without H2O can be calculated to 23(O) with IMA97-recomm ended normalization for Fe3+ and Fe2+ values. To test the program, over 500 analyses were calculated using the three options. The first comprehensive test of the third option successfully estimated Fe2+ (R-2 = 0.88), but beca me less successful for Fe3+ (R-2 = 0.42) estimation. Problems in the normal ization of Mn3+- and Mn2+-bearing amphiboles and in the IMA97 sodic amphibo le classification procedure emerged for Mn-rich amphiboles. This necessitat ed the proposal and implementation with the program of a simplified sodic a mphibole classification scheme. A new coloured amphibole classification cha rt accompanies the program. (C) 2001 Elsevier Science Ltd. All rights reser ved.