Study on Freshwater Non-nucleated Pearl by Miro-Laser Raman-Mapping Technology

In recent years,the study of vaterite in pearl becomes more and more popular.In the paper,the two mineral phases in the freshwater non-nucleated pearl samples are investigated according to the differences of characteristic Raman spectra between the aragonite and vaterite.The position,shape and size of the vaterite in the freshwater non-nucleated pearl samples are primarily confirmed by micro-laser Raman-mapping technology.The results show that the vaterite is usually distributed around the nucleus and few on the surface of the pearl samples.Through the scanning electron microscope(SEM),there are different micromorphology characteristics between vaterite and aragonite on the surface of the pearl sample.Meanwhile,the orientation effect of Raman spectra occurred in the pearl samples and Raman effect of the organic pigment have also been discussed.