corundum, synthetic corundum.7, gems

Heaton reviews the contemporary production of artificial precious stones and the methods available for distinguishing them from their natural counterparts. Particular attention is given to synthetic ruby and sapphire, including the processes developed by Frémy and Verneuil, the materials and apparatus employed, and the physical and optical properties of the resulting products. The paper discusses the identification of artificial stones by microscopic examination, inclusions, internal structure, and other diagnostic characteristics, and considers imitation and reconstructed stones alongside true synthetic products. Published at a time when flame-fusion corundum was becoming commercially important, it provides a useful contemporary account of the problems that synthetic gemstones posed for jewelers and gemologists.