books.google.ca - Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome, and the most precious of all gemstones.The first...http://books.google.ca/books/about/The_World_of_Opals.html?id=vGewAkLkmvIC&utm_source=gb-gplus-shareThe World of Opals
