Acta Petrologica et Mineralogica

This study comprehensively analyzed the basic gemological characteristics, X-ray fluorescence spectroscopy (XRF), infrared spectroscopy, Raman spectroscopy, and other aspects of green apophyllite samples with different tones in the Huanggangliang area of Inner Mongolia, and systematically explored the chemical composition and spectral characteristics of green apophyllites samples with different tones. Through high-pressure X-ray diffraction (HPXRD) spectroscopy testing, the crystal structure characteristics of the mineral under high-pressure environment were analyzed in depth, providing key clues for revealing the stable depth of existence of apophyllites after subduction into the crust during geological movement. The research results indicate that the apophyllites in the Huanggangliang area of Inner Mongolia belong to fluorine apophyllites, the content of Fe³⁺ and crystalline water exert a significant influence on the intensity of the green color in apophyllites. In the HPXRD experiment, as the pressure increases, the axial length and cell volume of apophyllites gradually decrease, especially the compression rate of the c-axis is higher than that of the a-axis. At the pressure nodes of 9.0 GPa and 15.3 GPa, a sudden change in compression rate was observed, accompanied by the emergence of new diffraction peaks and the splitting and disappearance of old diffraction peaks. This discovery reveals two distinct phase transitions of apophyllites crystals in high-pressure environments. This study provides strong scientific basis for identifying apophyllites and searching for mineral resources, and also provides a new perspective and understanding for further research on apophyllites in the field of geology.

apophyllite; Huanggangliang in Inner Mongolia; chemical composition; crystal structure; spectral analysis