Favrile glass is distinguished by brilliant or deeply toned colors, usually iridescent like the wings of certain American butterflies, the necks of pigeons and peacocks, the wing covers of various beetles. (Louis Comfort Tiffany)
In 1865, Tiffany traveled to Europe, and in London he visited the Victoria and Albert Museum, whose extensive collection of Roman and Syrian glass made a deep impression on him. He admired the coloration of medieval glass and was convinced that the quality of contemporary glass could be improved upon. In his own words, the "Rich tones are due in part to the use of pot metal full of impurities, and in part to the uneven thickness of the glass, but still more because the glass maker of that day abstained from the use of paint."
Tiffany wanted the glass itself to transmit texture and rich colors, and as such developed Favrile.