corundum, synthetic corundum.7, gems

Gunawardene describes the identification characteristics of the Knischka synthetic ruby, concentrating on features observable by the practising gemologist. The article discusses the distinctive crystal-growth morphology of Knischka material and illustrates its characteristic internal features, including growth structures and inclusions associated with the synthetic growth process. Particular emphasis is placed on microscopic examination and on distinguishing Knischka ruby from natural ruby and other synthetic corundum. The article is extensively illustrated, with 30 figures, 29 in colour, providing practical examples of the diagnostic features. This appears to be a more practically oriented treatment of material Gunawardene had discussed in greater detail in his 1983 Journal of Gemmology paper.