It is a fully updated version and designed as a Companion volume to Ruby & Sapphire: A Collector's Guide. It is made specifically for gemologists, appraisers and students.
It is a revised version and based on the famous book of Richard W. Hughes' 1997 classic, Ruby & Sapphire and with much more updates to it. It covers every aspects of the subject and can be used as a reference from A to Z about the stones. All the informations are widely covered - History, sources, prices, quality analysis, synthetic treatment, etc !!!
It is The Most Definitive Reference on the Subject !!!