Gemmological and Mineralogical Characteristics of Green Trapiche-Like Quartz from Huanggangliang, Inner Mongolia, China

Green quartzs are rare in nature, trapiche-like quartzs are scarce on the market, and research on green quartzs with the trapiche-like phenomenon is even rarer. In this paper, conventional gemmological instrument tests, X-ray fluorescence spectroscopy, Raman spectroscopy, and Fourier infrared spectroscopy were carried out on 2 raw trapiche-like green quartzs from Huanggangliang, Inner Mongolia, and on slices made from them. The results show that the samples are natural with a light green to greyish-green colour and the crystal form is developed as hexagonal column and 2 groups of rhombic faces. The trapiche phenomenon in the cross-section is caused by the zoned distribution of inclusions, suggesting that the sample belongs to the trapiche-like quartz. Six fixed arms of the trapiche-like pattern extend toward the vertices of the hexagonal cross-section. The triangular zones demarcated by those arms exhibit reduced transparency due to densely distributed oriented tubular inclusions, together with the more transparent arms to form the trapiche-like pattern. The oriented tubular inclusions consist of numerous discontinuous, elongated, irregular fluid inclusions perpendicular to the hexagonal prismatic faces. The fluid inclusions are primarily composed of liquid water with a certain amount of CO₂. Additionally, the quartz contains a large amount of green fibrous ferro-actinolite, and apophyllite is observed adhering to the surface. The trace elements detected by X-ray fluorescence spectroscopy include Fe, Al, Mg, P, K, Ca. The green colour is mainly caused by the green fibrous inclusions, and the ions and inclusions work together to make the peripheral ring appear grey-green.