natural ruby, synthetic corundum.7, gemology, inclusions.5, gems

Schmetzer presents a comprehensive study of the identification and separation of natural and synthetic rubies, based on examination of approximately 900 natural and 350 synthetic stones. After reviewing the mineralogy and crystallography of corundum, he describes five principal methods of synthetic ruby growth and the analytical techniques employed, including microscopy, UV-visible and infrared spectroscopy, ultraviolet fluorescence, goniometry and chemical analysis. The principal emphasis is on microscopic inclusions and internal growth structures: rutile, boehmite, twinning and characteristic growth features are discussed as evidence of natural origin, while diagnostic inclusions and structures in synthetic material are related to particular growth processes and manufacturers. Natural rubies from 15 localities are described and compared, followed by similarly organized accounts of 11 types of synthetic ruby. The work is extensively illustrated and intended as a practical reference for determining whether a ruby is natural or synthetic and, in many cases, establishing its geographic source or method of synthesis.