Completely revised and expanded with 11 new chapters: Jade / Demantoid Garnet / Natural Nacreous Pearls / Conch Pearls / Sunstone / Moonstone / Peridot / Cobalt Blue Spinel / Red -Pink Spinel / Golconda (Type IIa) Diamonds. Five new introductory essay: Blue-white diamonds / Jadeite / Natural Pearls / Spinel / Feldspars. Plus 278 color photographs (171 additional) which include exclusive images from major museum collections and the latest auction market icons. The definitive book for anyone wanting to learn how the best gemologists in the world evaluate precious gems, and what makes one stone merely a good stone versus a truly fabulous museum quality gem. The author, Richard Wise, is one of the world's foremost gemologists.