Quezal peacock blue on plum, gold lined, 9"

To get this color combination, gold decoration is placed on the plum layer. With the precise application of heat, the blue colorant in the plum layer bleeds into the gold layer producing the peacock hue. On the paper label, the number 1521 is written in the No. space and the word "Special" in the Dec. space. This shape becomes No. 1730 in Durand glass, and the designation "Special" continues to be used for the Dec. in Durand (see Revi, "AMERICAN ART NOUVEAU GLASS, page 206). Might this be because of the "Special" skill and technique required? The dark ring around the body is just a lighting artifact in the photo. (1987)