Why I am putting 3 stars for the book is that though it covers all rocks and gems and a lovely presentation , the detail and depth required for proper visual identification of gem stones is missing through pics and words. For example the book shows a blue rough sapphire which is great but what about pics of various white and yellow sapphire rough. This book is good for coffee table or a beginner who is interested in gemology. Otherwise, the book is fantastic.
Loaded with information and fascinatingly illustrated.
Production standards are excellent as with all DK definitive visual guides.
The only thing irksome is the small font size. This problem would not have been there if there if the book had a larger page size. Maybe there is indeed a larger format version but the one I procured has this problem.
Nevertheless, excellent value for money and a great book overall.