Raman Spectroscopy of Minerals

Abstract

I WISH to show that the technique of Raman spectroscopy can be usefully applied to the problem of the identification of minerals and can, in certain circumstances, provide some structural information. The method can be used for a wide variety of minerals, though here I report results only for those containing MO₃ or MO₄ functional groups (carbonates, silicates, phosphates, arsenates, vanadates, sulphates, chromates, molybdates, tungstates). Although infrared spectra of minerals have long been studied¹ there have been no systematic Raman studies apart from some very early work on silicates and sulphates²; there are some elegant studies on single crystals of a few specific minerals such as barytes³, gypsum⁴ and quartz⁵. All the minerals studied here have known structures or known lattice space groups, and in most cases infrared data are available for them; thus there are two checks on the interpretation of Raman spectra. It must be emphasized that Raman and infrared spectroscopy are complementary techniques and should, wherever possible, be used together, though valuable information may be derived from the use of one method alone.