This 1913 book does a very good job of describing gem materials, sources, rules, working methods and evaluation criteria. It is 117 readable, interesting pages. The author’s goal was not for it to be the authoritative book but rather to have the most useful and interesting information, to provide stories for his employees to use in selling jewelry. He was synthesizing from the books and the field out there at his time to make it understandable and interesting. A good book.