Gem Testing - Hardcover

Gem Testing.

hardcover. Zustand: Sehr gut. 9th ed. 457 p. With a personal inscription. Good copy with slight marks of age and use. The pages are clean. - - Since 1971, when the eighth edition of Gem Testing appeared, developments in gemmology have taken place very rapidly. The techniques of crystal growing are now so well understood that almost any gemstone, if required, can be produced in the laboratory, in addition many hard crystalline substances not found in nature have been manu factured and used to represent natural stones - in particular diamond, This long-established work is a practical manual on gem identification, designed to aid all those (students of gemmology, jewellers and even experi- enced gemmologists) who need to identify gem- stones and to distinguish natural stones from the numerous man-made substitutes now available. The preliminary chapters give a clear and thorough description of the physical and optical characters of gem minerals and of the apparatus by which these properties can be observed and measured. This general section ends with an important chapter describing all types of synthetic and Imitation stones at present on the market, and their distinctive characters. There follows a series of chapters on the well-known gemstones, giving a full description of their properties and those of the synthetic or substitute materials with which they may be confused. The appendix includes a glossary, an explanation of crystal systems, a summary of the main gem species in alphabetical order, tables of constants and a reading list. The tests and methods described are based, as far as possible, on the author's many years of experience as Director of the Gem Testing Laboratory of the London Chamber of Commerce, and include techniques that were originally evolved in this famous laboratory. In this ninth edition, a large number of new synthetic gem materials and several new varieties of natural stones are fully described and the means of identification given. New instruments such as various forms of reflectivity meters are described. Notes on testing industrial diamond powders have been added, and a description of ivory and its substitutes is now included. - - How to Use this Book - - Collecting, Handling, and Housing Gemstones - - Refractive Index and its Measurement - - Double Refraction and Dispersion - - Colour, Colour Filters, and the Dichroscope - - The Specific Gravity of Gemstones and How to Measure it - - The Use of the Microscope - - Detection of Synthetic, Imitation and Composite Stones - - The Use of the Spectroscope - - Fluorescence as an Aid to Identification - - The Identification of Diamond - - The Identification of Ruby - - The Identification of Sapphire - - The Identification of Emerald - - - Aquamarine and Alexandrite - - - Zircon - - - Topaz and Other Yellow Stones - - - Pink, Mauve, or Lilac Stones - - - Brown and Orange Stones - - Quartz, Chalcedony, and Opal - - - The Garnet Family - - - Tourmaline, Peridot, and Spinel - - - Jade and Jade-like Minerals - - - Turquoise and Lapis Lazuli - - - Cat's-eyes, Star-stones, and Others - - - Amber, Tortoiseshell, Coral, Jet and Ivory - - - Pearls: Real, Cultured, and Imitation. ISBN 9780408004404 Sprache: Englisch Gewicht in Gramm: 742. Artikel-Nr. 1278298

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