Vaterite or aragonite observed in the prismatic layer of freshwater-cultured pearls from South China  

作　　者：Hongyan Ma Anan Su Beili Zhang Ru-Kang Li Longchang Zhou Baoli Wang 

机构地区：[1]College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China [2]National Gemstone Testing Center, Beijing 100013, China

出　　处：《Progress in Natural Science:Materials International》2009年第7期817-820,共4页自然科学进展·国际材料（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 20566002)

摘　　要：A prismatic layer is present in both freshwater-cultured pearls and seawater-cultured pearls, The phase structure of the prismatic layer of freshwater-cultured pearls is investigated for the first time and novel findings are reported in this paper. X-ray diffraction （XRD）, optical microscopy （OM） and micro-infrared （IR） spectroscopy were used to characterize the crystallized layers of high and low-quality freshwater-cultured pearls. Results show that there is no calcite in the prismatic layer of freshwater-cultured pearls, which is different from what was found for seawater-cultured pearls. We found that an aragonite phase was present in the prismatic layer of high-quality freshwater-cultured pearls and that a vaterite or aragonite phase was present in low-quality pearls. Based on this study an internal factor that influences the quality of freshwater-cultured pearls is discussed.@2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.A prismatic layer is present in both freshwater-cultured pearls and seawater-cultured pearls. The phase structure of the prismatic layer of freshwater-cultured pearls is investigated for the first time and novel findings are reported in this paper. X-ray diffraction (XRD), optical microscopy (OM) and micro-infrared (IR) spectroscopy were used to characterize the crystallized layers of high and low-quality freshwater-cultured pearls. Results show that there is no calcite in the prismatic layer of freshwater-cultured pearls, which is different from what was found for seawater-cultured pearls. We found that an aragonite phase was present in the prismatic layer of high-quality freshwater-cultured pearls and that a vaterite or aragonite phase was present in low-quality pearls. Based on this study an internal factor that influences the quality of freshwater-cultured pearls is discussed.

关 键 词：VATERITE ARAGONITE Prismatic layer Freshwater-cultured pearls 

分 类 号：O123.2[理学—数学] TS933.23[理学—基础数学]