corundum, synthetic corundum.7, synthetic ruby, flux, Ramaura, gems

Gunawardene examines the gemmological properties and identification characteristics of the newly introduced Ramaura synthetic ruby, marketed by Overland Gems Inc. of California and first announced at the 1983 Tucson gem and mineral show. The material is flux-grown and was commercially available as faceted stones as well as lower-grade material, single crystals and crystal clusters. The study describes the external crystal morphology, standard gemmological properties, fluorescence and absorption characteristics, and especially the microscopic features of Ramaura ruby. Particular attention is given to flux-related inclusions and growth structures that distinguish the material from natural ruby and from other contemporary synthetic rubies. The author stresses that some specimens may be relatively straightforward to recognize, whereas cleaner stones require careful microscopic examination and comparison with the diagnostic features of other flux-grown synthetics.