corundum, ruby, sapphire, synthetic corundum.7, synthetic ruby, synthetic sapphire, gems

Chudoba and Gübelin provide a practical guide to distinguishing natural gemstones from synthetic counterparts, combining a short history of artificial gem production with detailed discussion of the principal manufacturing methods and their diagnostic consequences. The Verneuil flame-fusion process, flux growth, and hydrothermal synthesis are described, together with the characteristic structures and inclusions they produce. Particular attention is given to synthetic ruby and sapphire, spinel, emerald, and other important gem materials, with comparisons between natural and laboratory-grown stones based on growth zoning, curved striae, gas bubbles, mineral inclusions, refractive properties, fluorescence, and other microscopic and physical features. The authors emphasize examination with the gemological microscope as one of the most powerful means of separation, supported by numerous photomicrographs illustrating inclusions and growth phenomena in both natural and synthetic gems. Conceived as a concise working manual for gemologists and jewelers, the book brought together the principal identification criteria then available at a time when synthetic gemstones were becoming increasingly sophisticated and commercially important.