jade, nephrite, Khotan, Hetian, Xinjiang, gems

A thematic collection of papers on the mineralogy, geological origins, physical properties, and cultural significance of yu, with substantial coverage of nephrite from Hetian, Manasi, and Xiuyan. Contributions examine mineral composition, colour, microscopic textures, and X-ray diffraction characteristics, alongside comparisons among producing regions. Other papers discuss the formation of nephrite and jadeitite through fluid–rock interaction and the historical importance of Hetian material in Chinese carving traditions.