It's a white porcelain cup with a mirrored finish -- until you rest it on the saucer. Suddenly it's a spectrum of bright colors, reflecting the pinwheel on the saucer. The curved sides compress the long petals into rows of diamonds. The cup will reflect any saucer it rests on, so try one or two from your own collection. Cup holds 6 oz. Not for use in the dishwasher or microwave.