Lustrous - I have done a search on ebay UK and there is much written about the maker/marketing Co "Dale Tiffany" within the results, from "high end glassblower based in California USA", "North American Glass Master Dale Tiffany" to the vase being part of "Tiffany's Milano Favrile line".
Oh, and not to forget this one "Dale Tiffany, Inc., the world's foremost developer of fine art glass lighting and accessories"
I guess the selling jury is still very much in its infancy ;-)