This guide provides concise, interesting and practical details on uncommon gems that are now being used by designers to create distinctive jewelry. It also lists the identification properties of the gems, where they are found, how they are used, why they are unique, how they are priced, and how to care for them.

Understanding gemstones in a geological context Gemstones are colorful treasures of the Earth that have captivated humans for thousands of years. The physical and chemical characteristics of each type of gem provide insights into the geological processes that created them. Geology and Mineralogy of Gemstones is a textbook aimed at upper-level undergraduate and graduate students. It presents the basic mineralogical and geological knowledge needed to understand gemstones and examines the characteristics and geological origins of different types of gemstone. Volume highlights include: Concepts in mineralogy Structure and chemical composition of minerals Geological processes that lead to the formation and movement of gemstones Equipment and tools used to examine gemstones and their physical properties The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

"Gems and Gemstones" features nearly 300 color images of cut gems, precious and semiprecious stones, gem-quality mineral specimens, and fine jewelry to be unveiled in the new Grainger Hall of Gems at the Field Museum in Chicago.

Each gem deposit-whether of primary origin in the parent rocks; or secondary as alluvial placers in valley floors, river gravels, or the sand of oceanic shelves presents an eloquent chronicle of the Earth's life story. It reveals to the expert the prodigious processes which formed the present crust of our planet, of which this volume discloses a small but exciting detail. The materials of the Earth's crust are the rocks. In this book, the author expounds on how they were formed, why they altered, why they became the cradles of precious gemstones, how they are categorized, and how they are now exploited by man. What initiates the growth of gemstones? How do they crystallize? Why do gemstones of the same species, originating from different sources, vary? What causes the occurrence of varieties? Why do diamonds, unlike other precious stones, occur not near the Earth's surface in its crust, but deep down beneath it in the upper mantle? These are only a few of the entrancing subjects discussed in this enlightening volume. The reader learns that the Earth is surprisingly alive and altering constantly-sometimes through slow and equable changes and at times by violent and tremendous cataclysms, events from which gemstones issue.

Gemstones of the World is truly the single volume that every hobbyist, jeweler, jewelry maker, and rockhound needs: it’s the cornerstone of the field. And this updated edition contains a host of new findings on "Gemstones for Collectors,” additional gems in the "Table of Constants,” and the "double fraction” figures that experts have long wanted--a very special new feature. All the gemstones are treated in their many variations: more than 1,500 full-color photos showcase each precious and semiprecious stone in both its rough, natural, and its polished and cut renditions. Each entry offers complete information on the gemstone’s formation, structure, physical properties, and characteristics, along with the best methods of working, cutting, and polishing it. There are even full treatments of lesser-known gems, from andalusite to vesuvian, and a special section is devoted to rocks as precious stones, including alabaster, onyx, obsidian, and fossils. Organic gem materials are also covered, such as coral, ivory, amber, and pearl. Charts and tables help collectors identify unknown gemstones and check for genuineness.

Gemstones is the first attempt in English to bring together the geological, mineralogical and gemmological developments that have taken place during the last thirty years. Though there have been many gemstone books published in that time, most have been concerned, understandably and rightly, with the science of gem testing and have covered that area very well. Details of the geological occurrence of many of the classic gemstones, and of nearly all those which have only recently been discovered, have been less adequately dealt with. Coverage has been restricted to a number of papers in a wide variety of geological and mineralogical journals. Gemstones hopes to get the balance right. In the preparation of the book all the journals and monographs in the field have been consulted so that the book should stand for some years as the authority to which gemmologists and others turn in the first instance. Ease of reference and depth of coverage make Gemstones both a reference book and a bench book. Acknow ledgements I am grateful to Brian Jackson of the Department of Geology, Royal Museums of Scotland who read the manuscript and painstakingly indicated places where amendment or alteration was needed. I am also grateful to the publishers of the books on which the line illustrations are based. The colour plates present in the book derive from a number of sources, which I would like to acknowledge as follows. Plates 1, 4-15 and 17 Crown copyright reserved.