Some more discussion on the characteristics of Tyrian. From Dick Stark of Bethesda, Maryland
Tiffany blue, red, brown etc. are all on calcite. Tyrian is a heat resistant homogeneous green glass like Pyrex. It is very unique.

Dealer, David Goldstein of Naples, Florida provides additional background on reheating glass.
Tyrian was supposed to shade in color from Green to Purple. The shading was achieved by reheating portions of the piece, and the extent and smoothness of the shading depended on the way the reheating was done. I believe that the Tiffany Blue pieces were an attempt to achieve the same sort of shading in blue pieces that Tyrian does with greens. There are several known examples of Steuben iridized blues that are darker than the Tiffany Blue pieces and these may represent another attempt to create a shaded blue color.

Carder was familiar with reheating as a color changing technique from his work in England. The Victorian shaded glasses such as Amberina, Burmese and Peachblow were known to him, and the patent information was readily available. Although this was mostly an American development, several English companies did similar shaded glasses and Webb obtained a license from Mount Washington to make Burmese in England.

The Steuben Burmese pieces, which are rarities, would actually be considered poor examples if they were Mount Washington Burmese. However, they and Tyrian are evidence of Carder’s work with reheating glass to effect color change.

Then a few more pictures of glass that will be sold at the closing event-auction at the Symposium on October 3, 2009