The most comprehensive, fabulous, fascinating book on turquoise available today, written by Joe Dan Lowry and his father, Joe P. Lowry.  Beautiful color photos of ancient museum pieces through the contemporary period of turquoise from all over the world. The most comprehensive study of stone including scientific methods of treatment, to grading, history of mines, usage and variety, basically everything you really wanted to know about turquoise.  One of the most important books to add to your library if you are a collector of this fine gemstone.