Designed by Frank Lloyd Wright for the Luxfer prismatic tile company and patented in 1897 these 4x4 inch glass tiles were set into the front transom of buildings to refract light striking the building and carry it deep into the interior. Thiis was in an age of gaslamp illumination so any additional light that could be brought into a building was a great benefit. The success of these tiles can be measured by the thousands that were installed and the many that remain in use today over 100 years later. Due to the manganese in the glass the tiles turn a subtle purple when exposed to sunlight over many years. This tile was salvaged from a building in the mid-west and is in perfect condition with no chips, flaws, or cracks. A lovely piece of architectural history that you can place in a sunny window and enjoy as the refracted light dances across the room.Of all the Wright designs for Luxfer only this one was actually put into production. Please see my other listings for Luxfer and Wright related items.