corundum, synthetic corundum.7, Verneuil, Czochralski, pulling, flux, hydrothermal, gems

This practical handbook surveys manufactured gem materials, their production, and the features used to distinguish them from natural gemstones and from one another. Its scope includes synthetic counterparts of natural gems, artificial materials without natural equivalents, imitations, composite stones, and selected treatments applied to natural material. A preliminary discussion clarifies terminology, reserving “synthetic” for products corresponding to natural substances in essential composition and structure, and emphasizes the importance of accurate descriptions in commerce. The first part introduces crystal structure, symmetry, growth, and imperfections before explaining the principal manufacturing processes. Flame fusion, hydrothermal synthesis, crystal pulling and other melt-growth techniques, flux growth, and skull melting are related to the materials they produce and to the inclusions, growth structures, and variations in physical properties that arise during manufacture. Irradiation, staining, and coating are considered as methods of altering appearance. General testing guidance discusses magnification, specific gravity, refractive properties, absorption spectra, color filters, reflectivity measurements, and cathodoluminescence, while a separate chapter explains the equipment and techniques used to photograph inclusions. The second part organizes identification information by material, covering diamond and its simulants, corundum, emerald and other beryls, alexandrite, spinel, garnet, quartz, opal, lapis lazuli, turquoise, organic materials, glass, doublets and triplets, and less common artificial crystals. Manufacturing histories and descriptions of commercial products are combined with diagnostic properties, comparisons with natural stones, and reports of individual specimens from the gemological literature. Particular attention is given to internal evidence such as curved growth striae, gas bubbles, flux residues, metallic inclusions, seed-related structures, and characteristic patterns in manufactured opal. Composite stones are examined through their junction planes, cement layers, bubbles, and differences between the optical properties of their components; immersion is especially useful for revealing their construction. The text stresses the continuing value of simple optical examination while placing individual observations within the broader evidence supplied by several tests. Color photomicrographs from Edward Gübelin’s collection illustrate characteristic inclusions and structures, supported by diagrams, spectra, and other photographs. An appendix explains trade names, and an extensive bibliography directs readers to manufacturing research and identification reports. Intended for working gemologists, dealers, and students rather than as an elementary gemology textbook, the book connects production methods with practical recognition across a wide range of manufactured and modified ornamental materials.