Multiexcitation Raman Spectroscopy in Identification of Chinese Jade

The high-fluorescence background of jade creates a great impact on the Raman spectra measurements that impedes their application in jade analysis and treatment, particularly with ancient jade. The five most important materials of Chinese ancient jade are amphibole, serpentine, turquoise, agate/chalcedony, and anorthite-zoisite (Dushan jade). This study comparatively analyzed the Raman spectra of different wavelengths' excitation light sources (514.5 nm, 632.8 nm, 785 nm) in identifying these Chinese jades, and this article discusses the most applicable ones to the analysis of different jade materials. The results show that although 632.8 nm He-Ne laser is appropriate for turquoise jades, generally speaking, Raman spectra produced by the 785 nm semiconductor laser and the 632.8 nm He-Ne laser are better for most kinds of jades than the spectra produced by the 514.5 nm argon ion laser, and both of them can be effectively used jointly in research by nondestructive phase analysis of Chinese ancient jade.