One way to create interest this holiday season is to show something unusual. Stingray coral from Alaska could be the answer. Mark Castagnoli of Placer Gold Design, Vancouver, B.C., uncovered this new gem from Prince of Wales Island. It's an attractive gem-quality fossil coral, identified as 400 million-year-old favosite coral that has been replaced by silica-rich calcium. It consists of a black outline of hexagonal honeycomb structure with white centers in a 1- to 2.5-mm cell size when cut on the horizontal. The trade name Stingray coral was chosen for its close resemblance to the skin of the stingray, which is used as an exotic leather as well as on the hilts of Samurai swords. (In Alaska, it's called arctic lace.) Also found in the same area is a more common, larger-celled, and more colorful fossil coral, which does not yet have any jewelry application. One likely use for stingray cora