For years, the magnificent yellow-green Peridot has been neglected as a lesser gem because it is tiny, easily produced, and relatively inexpensive; it is frequently simply considered the August birthstone. For centuries, its popularity has risen and fallen. However, a recent revival is bringing to light what Peridot enthusiasts have long known: this is a genuinely exceptional stone. The Gemological Institute of America has dubbed peridot “the extreme gem,” and it is one of only two gems—the other is diamond—that are born of fire and brought to light by the powerful forces of earthquakes and volcanoes. While these Peridots are...