Gemstones of the Worldis 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 wanteda 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.