Objective

2

To analyze the polarized light microscopic characteristics， the composition of physical phases and their relative contents of Maifanitum from different origins， and to establish the Fourier characteristic fingerprint of Maifanitum powder crystals by X-ray diffraction（XRD）.

Method

2

A total of 26 batches of Maifanitum samples were selected， and the microscopic characteristics of the sample powders and grinding flakes were observed by polarized light microscopy under single polarized light and orthogonal polarized light， and the main phase compositions and their relative contents were analyzed by powder crystal XRD technique， and the XRD Fourier characteristic fingerprint of Maifanitum was established. The incident light source of XRD was Cu target K

β

radiation， the light tube voltage and light tube current were 40 kV and 40 mA， respectively， the divergence slit was 1°， the scattering slit was 1°， the receiving slit was 0.2 mm， the scanning speed was 5°·min

-1

with continuous scanning and scanning range of 5-90°（2

θ

）， and the step length was 0.02°.

Result

2

The polarized light micrographs of powders and grinding flakes of Maifanitum were obtained， and the main phases were plagioclase， potassium feldspar and quartz， and a few samples also contained illite， pyrite， iron dolomite， calcite， iron amphibole and chlorite， etc. The relative total content of feldspar phases was 61.9%-82.4%， and the relative content of quartz was 12.6%-33.6%. The XRD Fourier fingerprint analysis method of Maifanitum with 13 common peaks as the characteristic fingerprint information was established， and the similarity calculated by the mean correlation coefficient method was 0.920 9-0.997 7， the similarity calculated by the mean angle cosine method was 0.940 5-0.998 4， the similarity calculated by the median correlation coefficient method was 0.921 1-0.997 5， and the similarity calculated by the median angle cosine method was 0.947 5-0.998 2.

Conclusion

2

The polarized light microscopic identification characteristics of Maifanitum are mainly plagioclase， quartz and potassium feldspar， and the technique of powder crystal XRD Fourier fingerprint analysis can be used for the identification of Maifanitum.