"Gemstones of the World" is the single, cornerstone volume that every hobbyist, jeweller, jewellery maker and rock-hound needs. This updated edition contains a new chapter on the treatment of gemstones, expanded information on what's 'New on the Market' and 400 additional stones. More than 1,500 full-colour photos showcase each precious and semiprecious stone in its rough, natural, 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; a special section on rocks as precious stones; and organic gem materials. Charts and tables (including the 'double fraction' figures that experts want) help collectors identify unknown gemstones and check for genuineness.