In the ninth and 10th centuries, Islamic glassmakers introduced new shapes, colors, and decorative patterns. This is among the most extraordinary stained glass objects that have survived from the Islamic period. The decoration focuses on a small, plump bird, perhaps a partridge or pigeon, surrounded by five fish. The entire surface of the bowl appears to have been coated with a copper-rich purple-red film before the decoration was drawn. The surface has a pale brown cast under reflected light, but the almost colorless glass, the coating, and the colorful stain come to life under transmitted light. The blue effect was not part of the design. Instead, it is due to weathering.