Trapiche-like Quartz from Dongwuqi Area, Inner Mongolia, China

Abstract

Trapiche-like quartz, which is scarcely reported, has a unique texture with a core, six arms, and quartz growth sectors. This study is based on six trapiche-like quartz from the Dongwuqi area, Inner Mongolia, China. Many experiments have been carried out to investigate the basic gemological characteristics, crystal structures, and chemical compositions. Magnification observation has demonstrated that the texture is due to the distribution of white-colored chalcedony in growth sectors. Spherical and black inclusions have been identified as iron oxides by Raman spectra and EPMA. EPMA and LA-ICP-MS data have shown that the samples were grown in an acidic environment with an average medium-high temperature of 325 °C. Combined with the crystal growth theories and infrared experiments, we propose that the trapiche-like texture is the result of dislocation glide, which is caused by the existence of water and changes in temperature.