Turquoise from Zhushan County, Hubei Province, China.

A relatively new source of gem-quality turquoise is hosted within slates in Zhushan County of China's Hubei Province. Rough and polished samples were studied using standard gemological methods, as well as FTIR and UV-Vis-NIR spectroscopy. The turquoise formed nodular, massive, and veinlet assemblages. Brown and black veinlets/patches and irregular white blebs were common, and micro scopic observation also revealed microcrystalline and spherulitic structures. In general, the nodular specimens were of the highest quality. The deposits show considerable potential as a commercial source of gem-quality turquoise. [ABSTRACT FROM AUTHOR]