Favrile glass is a type of iridescent art glass
designed by Louis Comfort Tiffany. It was patented in
1894 and first produced in 1896. It differs from most
iridescent glasses because the color is ingrained in
the glass itself, as well as having distinctive coloring.
Favrile glass was used in Tiffany's stained-glass windows.
The original trade name Fabrile was derived from an
Old English word, fabrile, meaning "hand-wrought" or
handcrafted.[8] Tiffany later changed the word to Favrile
"since this sounded better".( taken from Wikepedia )