jade, nephrite, China, Xinjiang, Khotan, gems

Xinjiang’s Gems and Jades (新疆宝石和玉石), by Yang Hanchen, Yi Xianrui, Yi Shuangting, Song Jianzhong, and Min Yaoming, is a comprehensive Chinese-language study of the gemstones and ornamental stones of Xinjiang, combining mineralogy, gemology, geological occurrence, historical exploitation, lapidary technology, and economic evaluation. Originally published in 1986, the work was subsequently revised and expanded; the supplied 2012 edition incorporates additional research, photographs, analytical data, and information about newly identified deposits. The authors begin with a historical survey of gemstone and jade exploitation in Xinjiang, tracing the use of ornamental stones from prehistoric times through successive Chinese dynasties and examining the longstanding importance of Hetian nephrite in Chinese material culture. Particular attention is given to the distinction between traditional Chinese classifications of yu and modern mineralogical terminology, with comparative chemical analyses of ancient and contemporary jade materials. The book then establishes a classification of gemstones and ornamental stones before examining individual mineral species and gem varieties. The gemstone chapters cover beryl, including aquamarine, heliodor, and green beryl; tourmaline in its various colours; garnet, including grossular and the material marketed as Altai emerald; corundum; spodumene; apatite; topaz; feldspar, including amazonite; diamond; diopside; scapolite; and sphene. For each material, the authors discuss crystal morphology, colour, transparency, refractive indices, specific gravity, chemical composition, optical properties, suitable cutting methods, quality requirements, and geological occurrence. Numerous tables provide quantitative chemical analyses, while absorption spectra, infrared spectra, X-ray diffraction data, and photographs of rough and fashioned specimens illustrate diagnostic characteristics. The extensive ornamental-stone section places particular emphasis on nephrite from the Kunlun Mountains and associated districts, examining white, greenish-white, green, black, yellow, and variegated varieties. The authors investigate the chemical composition and microstructure of nephrite, including its fibrous amphibole aggregates, characteristic textures, mineral inclusions, colour variations, and physical properties. Detailed comparisons are made between nephrite from Hetian, the Kunlun Mountains, and other Chinese and foreign localities, supported by chemical analyses, microscopic photographs, and infrared spectra. Geological discussions describe the formation of nephrite deposits through metamorphic and metasomatic processes, particularly reactions involving carbonate rocks and intrusive bodies. Additional ornamental materials include serpentinite, quartz, rock crystal, agate, chalcedony, jasper, turquoise, lilac-coloured ornamental stone, wax-yellow stone, and several locally named varieties whose commercial terminology does not necessarily correspond to internationally recognized mineral species. The sections on agate illustrate numerous patterns, including banded, onyx, lace, and dendritic varieties, while those on turquoise examine chemical composition, colour, texture, and geological occurrence. Historical illustrations of Chinese jade carvings complement technical discussions of cutting, polishing, grading, and craftsmanship. The concluding chapter classifies gemstone and ornamental-stone deposits according to their geological origins, describes the relationships between mineralization and host rocks, and identifies prospective areas for exploration throughout Xinjiang. The book is especially valuable for its regional geological observations, mineralogical analyses, locality information, and detailed treatment of nephrite, providing an important Chinese-language reference for researchers investigating Central Asian gem deposits, the history of the Chinese jade trade, and the scientific identification of Xinjiang’s ornamental stones.