APPLICATION OF COMBINED RAMAN SPECTROSCOPY AND ELECTRON PROBE MICROANALYSIS TO IDENTIFY PLATINUM GROUP MINERALS

摘要

The identification of minerals that occur as tiny and rare phases such as most of the natural platinum group minerals (PGM) is a challenging target. The main reason for that resides in their size (generally less than 10 μm) and mode of occurrence (i.e., polyphasic aggregates) that prevents any XRD structural study. Raman spectroscopy is innovative and complementary methodology with a potential to identify and to better characterize the PGM. The Raman spectra of only a limited number of PGM's are known (about 24), and they are presented in this study. They can be directly used to identify or verify small sized PGE-bearing phases that were detected by reflection microscopy or electron probe analyses. Most PGM's belong to the elements (about 30) and the sulphides (about 90). PGE-bearing oxides and hydroxides are not yet represented by minerals, but abundant spectra are available from physical chemistry, which are also presented in this study. These spectra may be highly valuable for the identification of these phases in nature.