Lusterware was first developed in the 9th century in Mesopotamia in the Middle East. The iridescent quality is the result of a metallic glaze that is applied during the last firing of the piece. Japan has produced Lusterware since the 19th century. It was in high demand from the 1920s to the 1940s. Popular pieces included tea sets, luncheon sets, wall pockets, vases, condiment sets, and ashtrays. Lusterware was popularized in Japan by brothers Ichizaemon & Toyo Morimura, and it was produced by factories all over Japan. There are 4 classes of Lusterware: Copper, Platinum, Gold, & Pink/Purple.