Study on the Relationship between the Relative Content of Moganite and the Crystallinity of Quartzite Jade by Raman Scattering Spectroscopy, Infrared Absorption Spectroscopy and X-ray Diffraction Techniques

Abstract

Quartzite jade is composed of α-quartz and another silica phase, moganite, which forms under low pressure and low temperature conditions. At present, there are few studies on the relationship between the relative content of moganite and the crystallinity of quartzite jade. In this study, some quartzite jade samples from four locations in China(Longling, Yunnan province; Huoshan, Anhui province; Hezhou, Guangxi Zhuang Autonomous Region, and Alxa League, Inner Mongolia Autonomous Region), were analyzed by Raman Scattering Spectroscopy, Infrared Absorption Spectroscopy and X-ray Powder Diffraction techniques. The results showed a negative correlation between the relative content of moganite and the crystallinity of quartzite jade. The higher the relative content of moganite, the lower is the crystallinity index of quartzite jade. The relationship of the intensity ratio of 502 cm-1/465 cm-1 in the Raman scattering spectrum and the crystallinity index of quartzite jade, could be expressed by the equation of Y=-0.36X+6.93(the correlation coefficient is-0.94). This research could not only offer some new ideas about qualitatively estimating the crystallinity of quartzite jade by non-destructive testing methods, but also provide some scientific evidence and theoretical restrictions for qualitatively evaluating quartzite jade.

Keywords

• crystallinity of quartzite jade
• relative content of moganite
• raman spectroscopy
• infrared spectroscopy
• x-ray diffraction