Research on Relationship between Colour and Raman Spectrum of Freshwater Cultured Pearl

The Raman spectra of freshwater cultured pearls with different colours have been studied. These pearls from China have not been bleached. It is found that there are similar spectra of organic substance in pearls with different colours and the spectra vary regularly with the colours. The regularity is significant for explaining colouration of pearl, appraising the colour and identification of black pearls.