Source MaterialIn 1997, Richard W. Hughes, American gemologist and gem trade personality, published Ruby & Sapphire, a widely read technical account of corundum intended for his fellow science geeks.Nearly 20 years later, Hughes has published another book on his two favorite gems, but it differs from his 1997 treatise in a significant way. “It is not one of scientific gemology, but instead represents what I call ‘humanistic gemology’—the relationship between gems and the people and places from which they come,” he writes in the foreword to Ruby & Sapphire: A Collector’s Guide.True to his word, the coffee-table tome views the far-flung locales where rubies and sapphires are mined—from Afghanistan to ­Vietnam—through the lens of the miners, traders, and cutters who handle the gems before they are transformed into jewels.“Not every single source is in there, but w