The Rietveld method using X-ray powder diffraction data was applied to selected skarn samples for quantitative determination of the present minerals. The specimens include garnet, clinopyroxene–garnet, plagioclase–clinopyroxene–wollastonite–garnet, plagioclase–clinopyroxene–wollastonite, plagioclase–clinopyroxene–wollastonite–epidote, and plagioclase–clinopyroxene skarns. The rocks are coarse- to fine-grained and characterized by an uneven distribution of the constituent minerals. The traditional methods for quantitative analysis (point-counting and norm calculations) are not applicable for such inhomogeneous samples containing minerals with highly variable chemical compositions. Up to eight individual mineral phases have been measured in each sample. To obtain the mineral quantities in the skarn rocks preliminary optical microscopy and chemical investigation by electron probe microanalysis (EPMA) were performed for the identification of some starting components for the Rietveld analysis and to make comparison with the Rietveld X-ray powder diffraction results. All of the refinements are acceptable, as can be judged by the standard indices of agreement and by the visual fits of the observed and calculated diffraction profiles. A good correlation between the refined mineral compositions and the data of the EPMA measurements was achieved.

中文翻译：

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利用X射线粉末衍射数据通过Rietveld方法对矽卡岩岩石进行定量分析

使用X射线粉末衍射数据的Rietveld方法应用于选定的矽卡岩样品，用于定量测定本矿物质。标本包括石榴石，斜长石-石榴石，斜长石-斜石-辉石-硅灰石-石榴石，斜长石-斜石-辉石-硅灰石，斜长石-斜石-辉石-硅灰石-闪石和斜长石-斜石-矽卡岩。岩石是粗粒到细粒的，其特征是组成矿物的分布不均匀。定量分析的传统方法（点计数和范数计算）不适用于这种不均匀的，包含具有高度可变化学成分的矿物的样品。每个样品中最多测量了八个矿物相。为了获得矽卡岩中的矿物含量，通过电子探针显微分析（EPMA）进行了初步的光学显微镜和化学研究，以鉴定Rietveld分析的某些起始成分，并与Rietveld X射线粉末衍射结果进行比较。所有的改进都是可以接受的，可以通过协议的标准指数以及通过观察和计算得出的衍射图的视觉拟合来判断。精炼矿物成分与EPMA测量数据之间实现了良好的相关性。可以通过协议的标准指数以及观察到的和计算出的衍射图的视觉拟合来判断。精炼矿物成分与EPMA测量数据之间实现了良好的相关性。可以通过协议的标准指数以及观察和计算出的衍射图的视觉拟合来判断。精炼矿物成分与EPMA测量数据之间实现了良好的相关性。