[Application of Raman spectrometer (785 nm) to jadeite test]

Jadeite is a greatly appreciated gemstone and often referred to as "the king of jade". Because of the advances in processing the treated jadeite is becoming more and more difficult for identification. NIR (785 nm) Raman spectrometer exhibits advantage of non-destruction, quickness, accurateness, and weak fluorescence interferences. This work reports such a research conducted using a NIR Raman spectrometer for a large number of jadeite samples. Based on the spectra collected and analysis there after performed, it is evident that the instrumentation and analysis methodology used have provided great information and assessment assistance in the application. It was found that the spectral response in the green area of a natural jadeite is much stronger in intensity than that in the white area. This is attributed to the key factor, the content of Cr3+ in the area. In contrast the spectral response in the green area of a treated jadeite is much weaker and additional Raman peaks start to show up on the high Raman shift side. This is the evidence of added fluorescence phenomenon and epoxyresin. It was also discovered that certain Raman features disappear compared to a natural sample. This indicates that the jadeite has been treated with acid and filled with colorless glue, which io turn destroyed the original exterior structure of a jadeite.