This is a Showa-era retro rainbow glass plate. It shines with aurora colors depending on the viewing angle, with a sun-like shape and petal-like patterns. It appears to be a vintage item manufactured during the Showa era. It was found wrapped in old newspapers in my grandmother's cupboard. It seems to have been stored for a long time. Diameter...approximately 14-17 cm As this is an old, used item, we ask for your understanding.