TABLE OF CONTENTS The Raman analysis of minerals (or molecules) has two distinct meanings. [1] For physicists and some chemists it means a theoretical and/or experimental study of the expected number of Raman bands for a given chemical composition and given structural space group, and of the different kinds of physical property attribution, especially symmetry (e.g. A 1g, E g etc., stretching, bending, torsion etc., optical vs. acoustic modes, rotation vs. translation vs. lattice modes, polarisations, Porto notation etc.) and of chemical property attribution (e.g. vibration of MgO 6, Si-O-Si, O-H etc.). For geologists and most mineralogists, and by extrapolation for gemmologists, archaeologists, art historians, restorers and curators, it means the identification of an unknown species by comparison of its Raman spectrum with standard reference Raman spectra in a database; this was originally called Raman fingerprinting . [2], [3] Like human fingerprinting by forensic scientists, the chance of finding identical spectral images for different species (or their liquid or solid-solution mixtures) is infinitesimal. The only problem is that it is necessary to have a very extensive database, and this still does not exist. The advent of Raman microscopy [25](RM) had a dramatic positive effect in stimulating research as it allowed the selection on a micrometre scale of which crystal to...
