Yogo The Great American Sapphire Author:Stephen M. Voynick To the surprise of many, the United States has emerged as a commercial source of what some gem experts consider the world's finest sapphire. Equally surprising is that the entire production of the gem comes from a little-known Montana mine named Yogo, which 60 years earlier had produced $25 million in fine-cut sapphires for the British. Yogo... more » is a historical treasure, but the story of Yogo sapphires is really just a beginning, for only now are South American diamonds, Colombian emeralds, and Burmese rubies being belatedly joined by a native American precious gemstone that is every bit their equal the Montana sapphire. The colorful story of the Montana mine that produces the prized Yogo sapphires has been updated in this revised edition. Included is the demise of Intergem and the humble beginning of Vortex, Inc.« less