珍珠显微结构及纳米矿物的电镜分析

ELECTRON MICROSCOPIC STUDY OF THE NANOMETER MINERALS AND MICROSTRUCTURE OF MARINE CULTURED PEARLS

采用SEM(扫描电子显微镜)和HRTEM(高分辨透射电子显微镜)技术,系统地研究了珍珠层及其微结构。发现珍珠质层是由有机质胶结的文石组成片状晶层,文石大量为六边形、不规则多边形和近圆形,并与有机质层交互平行叠置。在棱柱层的柱状晶体周围也有纤维状、胶状有机质。同时,在棱柱状和片状文石晶体的截面上,含有大量纳米级的圆形、椭圆形等形状的有机质、气液包裹体或孔洞。其中许多部位的有机基质中不同程度地显现出晶格条纹像,均为纳米矿物所致。以上结果均表明珍珠层具有有序、精细、多层次、整体性好等优良的结构特点。这一结论对于探讨珍珠的成因、机械强度及医药保健性能等方面均具有重要的意义。

SEM （Field Emission Scanning Electron Microscope and Thermal Field Emission Environmental SEM-EDS-EBSD） and HRTEM （High Resolution Transmission Electron Microscope） were used to study the pearl nacre and its microstructure. The result showed that the pearl nacres are composed of parallel and alternative organic material layers and sheet aragonite crystal layers. The aragonite micro-crystals are dominantly present as hexagons, anomaly polygons and nearly spheres, and are cemented by organic materials. Fibrous and gel-like organic materials also surrounded the crystals of prismatic layers. Meanwhile, lots of round or ellipse nanometer organic materials, gaseous-liquid inclusions and pores were observed on the section of the prism and sheet aragonite crystals. In addition, some lattice fringe images of nanometer -sized minerals were also observed on the surface of organic matrix in many parts of the pearl nacres. All results above indicated that the pearl nacres have the good structure characteristic of ordering, fineness, multistage, and holism. This conclusion is of important significance in discussing the formation, mechanical strength and medical applications of pearls.