Applications of Raman spectroscopy to gemology

Being non-destructive and requiring short measurement times, a low amt. of material, and no sample prepn., Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of lab. Raman and micro-Raman spectrometers and of portable Raman systems in the gemol. field is given, focusing on gem identification and on the evaluation of the compn., provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important org. materials used in jewelry, i.e., pearls and corals. FigurePictures of a pyrope-almandine garnet and of a needle-shaped inclusion.