Female upperside, fore wing: bluish purple, paler outwardly, in certain lights with a resplendent iridescence; costa and apex very broadly, termen somewhat more narrowly fuscous black.
en.wikipedia.org In addition to simple body colour, minerals can have various other distinctive optical properties, such as play of colours, asterism, chatoyancy, iridescence, tarnish, and pleochroism.
en.wikipedia.org Paradox externally appears as a slightly luminescent soap bubble with a diameter of 50 kilometers, with iridescence similar to that of a real soap bubble.
en.wikipedia.org A pileus cloud at the top of a storm cloud diffracts the sun's light creating an iridescence.
www.climatecentral.org