Structural coloration has potential for industrial, commercial and military application, with biomimetic surfaces that could provide brilliant colours, adaptive camouflage, efficient optical switches and low-reflectance glass. The bright gloss of buttercups is produced by thin-film reflection by the epidermis supplemented by yellow pigmentation, and strong diffuse scattering by a layer of starch cells immediately beneath. The most brilliant blue coloration known in any living tissue is found in the marble berries of Pollia condensata, where a spiral structure of cellulose fibrils produces Bragg's law scattering of light. In the few plants that exploit structural coloration, brilliant colours are produced by structures within cells. Many of these photonic mechanisms correspond to elaborate structures visible by electron microscopy. Some cuts of meat also show structural coloration due to the exposure of the periodic arrangement of the muscular fibres. In animals such as on the feathers of birds and the scales of butterflies, interference is created by a range of photonic mechanisms, including diffraction gratings, selective mirrors, photonic crystals, crystal fibres, matrices of nanochannels and proteins that can vary their configuration. Different colours therefore appear at different angles. The geometry then determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Young described iridescence as the result of interference between reflections from two or more surfaces of thin films, combined with refraction as light enters and leaves such films. Structural coloration was first observed by English scientists Robert Hooke and Isaac Newton, and its principle – wave interference – explained by Thomas Young a century later.

For example, peacock tail feathers are pigmented brown, but their microscopic structure makes them also reflect blue, turquoise, and green light, and they are often iridescent.

Structural coloration in animals, and a few plants, is the production of colour by microscopically structured surfaces fine enough to interfere with visible light, sometimes in combination with pigments. The brilliant iridescent colors of the peacock's tail feathers are created by structural coloration, as first noted by Isaac Newton and Robert Hooke.

The eyes of ara color wheel