[Study on XRD and infrared spectroscopy of nephrites from Xinjiang and Xiuyan, Liaoning]

The nephrite species with different colors from Xinjiang and Xiuyan, Liaoning, including gray nephrite, yellow nephrite, white nephrite, jasper and He-Mo nephrite, a special nephrite from Xiuyan, were selected for the present study. The gemological testing method, infrared absorption spectroscopy and X-ray powder diffraction were used to analyze and compare the gemological characteristics of the nephrite with different colors and textures from the above localities, in order to understand the similarities and differences between these nephrites with similar colors but different origin, and provide a theoretical basis for the identification of the nephrite origin. The results show that the nephrites from Xinjiang and Xiuyan, Liaoning province have similar gemological properties. They have similar refractive index of 1.60-1.62 and density of 2.660-3.020 g x cm(-3), and only the density has some differences with different colors. The fluorescence.characteristics are not obvious in these nephrites. The major constituent minerals for these nephrites are tremolite, and small amounts of clay minerals such as chlorite and illite are found in the jasper from Xinjiang. Based on the X-ray powder diffraction analysis on the different types of nephrite from two localities, it was shown that the character of spectra peaks and diffraction intensity of different types of nephrite can reflect the texture of the nephrite and the size of crystalline particles to some extent. The infrared absorption spectra are similar for the nephrites from two localities. The infrared absorption spectrum does not make sense to identify the origin and species of nephrites.