Optically variable ink uses finely powdered iridescent glitter. Iridophores are structures that produce iridescent colors with a metallic sheen. It is usually reddish brown or reddish violet, iridescent dorsally, and pale yellow ventrally. The sunset moth is black with iridescent red, blue and green markings. This leaves ions and iridescent luster behind. The body feathers of both sexes are a mixture of bronze and green iridescent color. The body is a bright iridescent green. Many are brightly coloured, often with iridescent feathers, particularly in the males. It has an iridescent bronze-green back, a pale grey chest and belly, and green flanks. The American crow is a large, distinctive bird with iridescent black feathers all over. They can sometimes be brightly coloured, and may be iridescent or even luminescent. Additionally, some specimens have iridescent feathers. The iris is blue and also iridescent. The American crow is all black, with iridescent feathers. Iridocytes are also responsible for the iridescent appearance of many dark-colored snakes.