beryl, synthetic beryl, emerald, USSR, gems

Lind, Henn and Bank examine 50 hydrothermally grown synthetic emeralds produced in the USSR, describing their gemological properties and diagnostic features. The material has SG 2.68–2.70, refractive indices nω 1.578–1.584 and nε 1.571–1.581, and birefringence 0.005–0.008. Microscopic characteristics include conspicuous zonal growth structures and growth tubes extending from black hexagonal platelets. The authors supplement conventional gemological testing with absorption spectroscopy and chemical analysis, including X-ray fluorescence and electron-microprobe methods, to characterize the material and provide criteria for distinguishing these Soviet hydrothermal synthetics from natural emeralds.