Abstract

In 1997, the International Mineralogical Association (IMA) revised the amphibole naming scheme making it necessary to amend the previous EMP-AMPH Macintosh program to the new rules. The AMPH-IMA97 program allows single input or automatic input of as many amphibole analyses as are available following a set input format. There are three options for calculation scheme of amphibole analysis: (1) complete chemical analyses can be calculated to 24(O, OH, F, Cl); (2) analyses with determined FeO and Fe 2O 3 but without H 2O can be calculated to 23(O) and (3) electron microprobe analyses with only total Fe determined and without H 2O can be calculated to 23(O) with IMA97-recommended normalization for Fe 3+ and Fe 2+ values. To test the program, over 500 analyses were calculated using the three options. The first comprehensive test of the third option successfully estimated Fe 2+ ( R 2=0.88), but became less successful for Fe 3+ ( R 2=0.42) estimation. Problems in the normalization of Mn 3+- and Mn 2+-bearing amphiboles and in the IMA97 sodic amphibole classification procedure emerged for Mn-rich amphiboles. This necessitated the proposal and implementation with the program of a simplified sodic amphibole classification scheme. A new coloured amphibole classification chart accompanies the program.

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