<p><i>A reference guide to gems, semi-precious stones and crystals.</i></p><p>Gemstones and crystals are used for jewelry, industry, lasers and precision technology. <b>Firefly Guide to Gems</b> is a practical, compact guide to the identification and use of precious and semi-precious stones, novelty stones, agates and crystals.</p><p>An introduction explains geology, chemistry and gemstone properties in clear and accessible terms. Key aspects of gemstones are explained such as crystal structures and optical and physical properties.</p><p>The first section of the book focuses on precious gems in their many forms, with illustrations of priceless jewelry. Practical information includes:<ul><li>Fashioning and cutting</li><li>Types and shapes of cut</li><li>Collecting</li><li>Handling and storing gemstones</li><li>Weighing and measuring stones</li></ul></p><p>The second and main section supplies complete descriptions of a wide range of gems, organized by chemical composition, for instance:<ul><li>Carbon (diamond)</li><li>Aluminum oxide (saphire and ruby)</li><li>Phosphate (turquoise)</li><li>Silica (opal)</li></ul></p><p>A fascinating profile of each gem is accompanied with color photographs of the raw crystal, common cuts, and finally polished for use in jewelry. At-a-glance charts provide technical details such as refractive index, crystal group, luster, hardness and cleavage for each gem. </p><p>Easy-to-read and abundantly illustrated, <b>Firefly Guide to Gems</b> is ideal for collectors and rockhounds.</p>