Characterization of polyene pigments in vaterite in Freshwater Cultured Pearls by Micro-Raman Spectrometry

SOLDATI, ANALIA L.

Hanoi, Vietnam

Workshop; The fourth International Workshop on Geo- and Material-Science on Mineral Resources of Vietnam; 2008

Different polymorphs of calcium carbonate have been reported to occur in freshwater cultured pearls (FWCP) from China and Japan. Vaterite, a meta-stable polymorph, can be found as lightly colored (light yellow, light brown or white, independent of the colour of the pearl) well defined areas near the centre of the pearls, but also as spots in the surface of good quality pearls. In this study we investigated the nature of the vaterite-related pigments by Micro Raman Spectrometry and compare them to the well known aragonite-related natural pigments in the same pearls.