From Dick Stark of Bethesda, MD
egerman, tiffany and quezal made an agate-like as well as a marbelized glass….actually at or before the turn of the cen. s.w. also made a moss agate but always faceted
it finely. carders glass is colored fragments suspended in a transparent bubbly batch…it is nothing like the other agates. it’s not too different from cluthra which was also made in scotland and later when kimball was at durand

From David Goldstein: I doubt if the Carder’s inspiration for Moss Agate was anything he saw at the Morgan Library. It is far more likely that he was inspired to create his Moss Agate by seeing examples of Frederich Egerman’s Lithyalin glass, which was developed in by Egerman in Bohemia in the 1830s. Many glassmakers throughout history tried to make glass that looked like stone but Lithyalin was probably the most successful. Another type of Moss Agate glass was developed at Stevens and Williams around 1888, which was while Carder was working there, but there is no indication that he was involved in its development.

If the goal of each of these glasses was to imitate stone, in my opinion Carder’s Moss Agate was much better than Stevens and Williams. However, I think Lithyalin was the best imitation of stone of any of these glasses. For the record, I would also like to point out that Tiffany made Agate glass during this period and Quezal developed another type of agate glass which was marketed as Innovation.