日本马氏贝珍珠化学组成的同步辐射X射线荧光光谱分析

采用同步辐射微区X射线荧光光谱技术,探测古铜色日本马氏贝珍珠剖面(珠核与珍珠层)的元素分布。测试结果表明,样品中主要含有Ca、Sr、Ba等3种碱土金属元素,Mn、Fe、Cu、Zn等4种3d过渡金属元素以及稀土元素,各元素在珍珠中表现出一定的空间分布规律:珠核表面稀土元素浓度最高,珍珠层和珠核的稀土元素浓度大致相当;Mn和Fe元素浓度自珠核浅表层向珠核表面有降低趋势;珍珠层内Mn和Fe元素浓度都出现大幅降低现象,且是在相同的圈层降低,显示其具有一定正相关性,推测二者大幅降低的圈层是平行层和棱柱层的分界,且Mn元素主要赋存于棱柱层;Ca与Sr、Ba元素的分布具有负相关性。

Chemical composition analysis of Pinctada martensii pearls from Japan by synchrotron radiation micro X-ray fluorescence

The chemical compositions and component distributions of Pinctada martensii pearls from Japan were investigated by synchrotron X-ray fluorescence spectrum. The results clearly show that these pearls contain Ca, Sr, Ba alkaline-earth metal elements, Mn, Fe, Cu, and Zn 3d transition metal elements and rare earth elements. In pearls, these elements present some distributions in space: the nucleus surface has the highest concentrations of rare earth elements and the concentrations of rare earth elements in the nacre and nucleus are roughly equal; in the nucleus there exists decreasing tendency of elements Mn and Fe from the superficial part to the surface; both Mn and Fe exhibit sharp fall in the same circle of the nacre, showing a certain correlation, and the place of sharp fall seems to be the dividing line of nacreous layer and prismatic layer; element Mn mainly exists in prismatic layer; the distributions of elements Sr and Ba show negative relationship with element Ca.