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Title: Effective guide to opal evaluation
Review: Downing's Opal Identification & Value provides a descriptive overview of opals, though it is short on technical data or gemmological information. The book emphasizes criteria for determining opal values, and here it performs a great service, because it lays out sensible-sounding and user-friendly guidelines. This book gives the reader an independent way to access the value of the opals offered in the marketplace, and helps her to make wise choices.
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