beryl, synthetic beryl, emerald, gems

Two techniques, flux and hydrothermal, have been used to grow emerald crystals, and various solvents have been employed. The lithium molybdate flux technique originated with Hautefeuille and Perrey in 1888 and was independently brought to feasibility by Nacken and at I.G.-Farben. This technique has proved to be commercially viable in the hands of Chatham and Gilson, who both perfected their processes independently of the Nacken and I.G.-Farben work, as well as of each other. Hydrothermal work culminated in the success of Flanigen and others at Linde, who found two acid mineralizers which gave satisfactory emerald growth; this process has not been commercially viable. Other crystal growth approaches of less significance are also discussed. Much confusion has existed because several flux techniques have in the past been misidentified as hydrothermal (there is, in fact, no evidence that even Nacken ever grew hydrothermal emerald) and some techniques claimed to produce crystals probably only yielded emerald glass, an inferior product. This account is based on original research, on an extensive literature search, as well as on many personal interviews. It is intended to clarify the confusing record as well as to present what is known about the current technology of gem emerald synthesis.