Steuben Art Glass Bowl, beautiful iridescent finish on eggshell white with fine colored rim, 9 3/4"....The first Gold Aurene glass was made by Steuben in 1904, and it was eventually produced in blue (as shown here), brown, red and green. The name of that first glass referred to the golden iridescence of the finish.The base glass used for these pieces was usually clear, amber or topaz. Tin and iron chloride sprays were used to give them their matte finish, according to The Collector’s Encyclopedia of American Art Glass by John A. Shuman III.When examined with magnification, thousands of tiny fractures can be seen in the surface of Aurene glass, which both reflect and refract light to give it the finish its sheen. If spots were missed when the spray was being applied, the resulting mirror gloss was considered undesirable.Blue Aurene came about in 1905 when cobalt was added to the Gold Aurene formula. Brown Aurene was made using brown glass sprayed with tin chloride. Alabaster and Calcite Steuben pieces were used as the base for Red and Green Aurene finishes decorated with flowers, leaf shapes, and a decorative technique known as feathering or trailing threads.Aurene was a Steuben staple until 1933 when production of these wares ceased. Vases were made more often than any other type of Aurene finished glass. All colors are considered to be rare and desirable collectibles, although Gold Aurene and Blue Aurene tend to be found most often. The marks frequently used on these pieces were "AURENE" and "STEUBEN AURENE" written in a rather amateurish fashion.When new, Aurene glass competed with glassware made by both Loetz in Austria and Tiffany in the United States. After first seeing Aurene glass, Louis Comfort Tiffany sued Steuben thinking his Favrile glass was being copied. When, in fact, the method used to make Steuben's version was actually very different than Tiffany’s process for imparting an iridescent finish. The suit reportedly never made it to court.