the Raman shifts which were found in the Raman spectra of violet pearls,1017,1295,2231 and 2609 cm-1,disappeared in the Raman spectra of white and red pearls;

• 紫色系列优质珠中的1017,1295,2231,2609 cm-1在纯白色珍珠和粉红色系列中均未曾出现;