The Surface Micro-Morphology Transition of Pearls Induced by Cerium

Abstract

The surface microstructure transition of pearl induced by rare earth element (REE) cerium (Ce) was investigated in micrometer scale range by means of scanning electronic microscopy (SEM). We found that pearls cultured in the control group (no REE Ce added) relatively grow slowly when there is in the culturing water, but the pearls grow quickly when REE Ce was added in the culturing water. At the same time, the former pearls were built up by aragonite blocks with spindly shape, but the latter pearls sampled in the REE test group are made of aragonite blocks with regular hexagonal shape. Moreover, the luster of the pearls free of REE Ce is relatively low because their surface were mainly build up by spindly aragonite blocks. On the contrary, the pearls with REE Ce have high luster since their surface were chiefly composed of regular hexagonal aragonite blocks that is the most idea blocks in crystallography. The results show that a quantity of Ce will promote the development and growth of pearls, and enhanced the lustrous of pearls significantly. Finally, we discussed the relevant of surface microstructure and lustrous of pearls to the concentration of REE in culture water by analyzing the influence of additive REE Ce on the surface microstructure