Characterization of Chinese hydrothermal synthetic emerald

Abstract

Synthetic emeralds grown hydrothermally in an alkali-free, chlorine-bearing solution have been manufactured in Guilin, China, since 1987. Diagnostic microscopic features include growth and color zoning as well as oriented needle-like tubes and cone-shaped voids ("nailhead spicules") that are typically associated with small chrysoberyl crystals. Also distinctive is the presence of chlorine in this iron- and alkali-free hydrothermal synthetic emerald. In addition, spectroscopic properties in the mid- and near-infrared are useful to characterize this new Chinese product; features in the 2500-3100 cm-1 range (also found in other chlorine-bearing synthetic emeralds) help distinguish it from natural emeralds. © 1997 Gemological Institute of America.