Gemmological Instruments

Gemmological Instruments deals with the developments in diamond grading equipment and gem testing instruments since the publication of the first edition in 1978. These developments include improvements in the versatility and styling of existing instruments such as the reflectivity meter, the composite spectroscope, and the refractometer. It also addresses the criticisms in the first edition and provides a discussion of the advantages and disadvantages of different gem testing equipment. This book is organized into 16 chapters that describe groundbreaking instruments like the thermal conductivity diamond testers and home-constructed items that while innovative have not yet been commercialized. There are also chapters dealing with microphotography and identification of synthetics and stimulants. This book also provides a listing of gemstone constants and characteristic inclusions in natural and synthetic gemstones. This book will be of interest to people interested in equipment for gem testing and diamond grading.

This edition has been completely revised to cover the latest methods of gem enhancement and identification, as well as the most up-to-date test instruments and laboratory techniques.

Vols. for July 1964 include Proceedings of the Gemmological Association of Great Britain.

Gemmology is a text for students preparing for the Gemmological Association's Preliminary and Diploma examinations. The book is more expansive and up-to-date than the author's earlier book, Beginner's Guide to Gemmology. The book deals with the practical and theoretical sides of gemmology. Tracing the background and science of gemmology, the book covers the gem material, geological formation, and occurrence of gemstones on the earth. The composition of gemstones from the atoms, elements, molecules, and compounds comprising them is analyzed, and the relationship between chemical composition and durability of the stone is explained. The basics of crystallography is mentioned as a tool toward understanding gemmology after which cleavage, parting, and fracture are done. A gemstone's durability and hardness and how the latter influences engineering tests and the mining techniques are compared. An important test technique to identify unmounted stones is the measure of specific gravity using displacement measurement methods and hydrostatic methods. After more descriptive details are given in identification of gemstones, whether these are synthetic or simulants, through a comprehensive explanation of the materials found in these other gemstones, the fashioning, through shaping or polishing, of gemstones is explained. Emphasis is given on the critical angle in which light rays pass in different rock densities, and then the cutting styles, gemstone polishing, and grading are discussed. Students studying for the Gemmological Association's Preliminary and Diploma examinations, jewelers, lapidarists, and diamond cutters, as well as those engaged in the hobby of gemmology, will find this book helpful and full of information toward their endeavors and hobbies.

Beginner's Guide to Gemmology presents the profiles of the principal gem materials. This book discusses the interesting characteristics of gemstones as the growing consumer market jewelry resulted in increased sales of gem testing instruments. Organized into 12 chapters, this book begins with an overview of the development of the science of gemmology. This text then explains the fundamental qualities necessary in a gem, including color, hardness, specific gravity, crystallography, refractive index, pleochroism, critical angle, luminescence, and absorption spectra. Other chapters consider the organic gem materials, including amber, ivory, coral, tortoiseshell, jet, ebony, and pearl. This book discusses as well the various methods used in the production of man-made gemstones and the commercial use in gem testing. The final chapter deals with the composition of synthetic gemstones. This book is a valuable resource for gemmologists and jewelers. Students who intend to become a qualified gemologist will also find this book extremely useful.