Gems Made by Man


Book Description




Artificial Gemstones


Book Description

This title is now in paperback for the first time.Artificial gemstones have been well established in the trade for some time, but now, following further refinements in their manufacture, gemmologists worldwide are facing increasing problems with identification.Today, gem-quality synthetic diamonds, once deemed impossible to produce, are becoming widely available, and, moreover, it is possible to create almost any major gemstone in whatever colour is desired. Then, too, the growth of diamonds by chemical vapour deposition is destined to present further problems. The synthetic products of the past, particularly of the 1960s, are still available, and are puzzling the newer generations of gemmologists who have not encountered them previously.In "Artificial Gemstones", Michael O'Donoghue provides the definitive guide to the various manmade substitutes thus enabling anyone handling gems to identify them accurately. Starting with the theory of synthetic gem manufacture and an explanation of the production methods used for growing and/or improving crystals - with their ornamental application - the book moves on to list and identify the materials themselves. Some of these have natural counterparts; others are new minerals and do not occur in nature. The author lists the identifying internal and external features and tests, and the book contains colour illustrations to display the inclusions found in transparent materials. The book is completed by an extensive bibliography and a useful appendix of trade names.Gemmologists, gem dealers, lapidaries, curators, amateurs and students of gemmology and mineralogy will all find this an indispensable addition to their bookshelves.




Color Encyclopedia of Gemstones


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Gems and Gemmology


Book Description

This book provides a lucid introduction to the basics of gemmology. It familiarizes archaeologists, art historians and conservators with the science of gemstones and allows them to understand the basic concepts of their provenance, typology and treatments. Which are the main types of gems? What treatments can be applied? How does one analyse gems? How can gems contribute to archaeometrical research? This volume is written by four experts in the fields of gemmology and archaeometry and addresses both students who need an introduction to this field and professionals who want to refresh their knowledge of the topic. This work is part of a series of introductory texts that deal with a broad range of materials-related topics in archaeometry.




Gems and Jewelry


Book Description

This new edition of the classic consumer guide to precious stones and their settings is packed full of color photographs and comprehensive information about gems in a portable format. Written simply and clearly, it answers consumers' questions and informs them of what they will encounter in the marketplace. 186 illustrations.




Mineral Facts and Problems


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Sapphire


Book Description

By the second half of the twentieth century, a new branch of materials science had come into being — crystalline materials research. Its appearance is linked to the emergence of advanced technologies primarily based on single crystals (bulk crystals and films). At the turn of the last century, the impending onset of the “ceramic era” was forecasted. It was believed that ceramics would play a role comparable to that of the Stone or Bronze Ages in the history of civilization. Naturally, such an assumption was hypothetical, but it showed that ceramic materials had evoked keen interest among researchers. Although sapphire traditionally has been considered a gem, it has developed into a material typical of the “ceramic era.” Widening the field of sapphire application necessitated essential improvement of its homogeneity and working characteristics and extension of the range of sapphire products, especially those with stipulated properties including a preset structural defect distribution. In the early 1980s, successful attainment of crystals with predetermined char- teristics was attributed to proper choice of the growth method. At present, in view of the fact that the requirements for crystalline products have become more str- gent, such an approach tends to be insufficient. It is clear that one must take into account the physical–chemical processes that take place during the formation of the real crystal structure, i.e., the growth mechanisms and the nature and causes of crystal imperfections.