Renowned gem expert Paul Deasy brings to life the fascinating world of opals. Part travelogue and part geologic study, Opals balances engaging narration with scientific information. Taking readers to the major opal deposits across the globe, Deasy explains the history of opal mining, how to judge opal quality, and a comprehensive reference section with gemological information even beyond the scope of opals. Appealing to jewelry enthusiasts and casual readers alike, Opals offers one of the most comprehensive looks at the subject in recent years.