Feature Gems & Gemology, Spring 2011, Volume 47, No. 1

Aquamarine from the Thuong Xuan District, Thanh Hoa Province, Vietnam

Vietnamese aquamarine is notable for its attractive color and well-formed crystals. Commercially significant deposits are known only from the Thuong Xuan District in Thanh Hoa Province, where the aquamarine (as well as topaz) have been mined from granitic pegmatites and associated eluvial deposits. Rough and cut samples were investigated by standard gemological methods, Raman and IR spectroscopy, and electron microprobe and LA-ICP-MS chemical analysis. The samples were characterized by a low concentration of alkalis and relatively high amounts of iron and cesium. Raman and IR spectroscopy showed the presence of CO2 and type I H2O in the beryl structural channels.