The book which will probably be found most useful by those who have mastered this little text is the work by G. F. Herbert-Smith, to which frequent reference has been made at the close of many of our chapters. It is thoroughly scientific, yet understandable, and is very complete on the scientific side of the subject.
Gem-Stones, G. F. Herbert-Smith, Jas. Pott & Co., N. Y.
For another work and one which contains information of trade character as well as scientific information about gems see Precious Stones by W. R. Cattelle, J. B. Lippincott & Co., Phila., or see A Handbook of Precious Stones, by M. D. Rothschild, G. P. Putnam's Sons, N. Y.
Gems and Gem Minerals, by Oliver Cummings Farrington, A. W. Mumford, publisher, Chicago, 1903, is another good general work on gems. Its color plates of rough gem minerals are especially good.
Those who are especially interested in the diamond should see The Diamond by W. R. Cattelle, The John Lane Co., N. Y., which gives a good account of its subject and is rich in commercial information, or Diamonds: A Study of the Factors which Govern their Value, by the present author, G. P. Putnam's Sons, N. Y., 1914.
Sir Wm. Crook's, the Diamond, Harper & Bros., N. Y., is very interesting, especially in its account of the author's visits to the S. African mines.
Students of pearls will find The Book of the Pearl, by Dr. Geo. F. Kunz and Dr. Chas. Stevenson, Century Co., N. Y., very complete. A smaller work, yet a good one, on pearls is The Pearl by W. R. Cattelle, J. B. Lippincott & Co., Phila., 1907. This book is strong on the commercial side.
An older work is Pearls and Pearling by D. Edwin Streeter, Geo. Bell & Co., London.
A work on gems and gem-cutting by a practical cutter is The Gem Cutter's Craft, by Leopold Claremont, Geo. Bell & Sons, London, but it should be said that very few trade secrets will be found exposed in the book.
On the subject of scientific precious stones The Production and Identification of Artificial Precious Stones, by Noel Heaton, B.Sc., F.C.S., read before the Royal Society of Arts, Apr. 26, 1911, is very fine. It may be had in the annual Report of the Smithsonian Institution for 1911, p. 217. It gives one of the best accounts to be had of the history of the artificial production of precious stones, especially of the corundum gems. It also contains a splendid account of how to distinguish scientific from natural gems.