Gemstone and Mineral Data Book

This working encyclopaedia of gemstones and minerals is the result of many years' research and field work on the part of John Sinkankas, the acknowledged dean of American gemologist. The author has derived much original information from lab-testing hundreds of materials and techniques himself. Here is a solid bedrock of working data for the lapidary and mineral field, a how-to plus reference volume that is both handy and complete: