As opposed to the classic rhinestones, which had a metal powder coating on the bottom side only, several companies have opted to mass-produce iridescent lead glass, by reducing the metal coating thickness and applying it uniformly, not using metal powder with a binder but by applying various forms of metal deposition (thin foil, vapor deposition, etc): Favrile glass by Tiffany in 1894, Carnival glass under the name "Iridrill" by Fenton in 1908, "Aurora Borealis" glass by Swarovski in 1956 and PVD-coated dichroic glass in the late 20th century, amongst many other decorative lead glasses coated with a thin metal layer sold under various commercial names such as "rainbow glass", "aurora glass" and such.