"Pearlescent" redirects here. For the type of paint, see Pearlescent coatings.
"Iridescent" redirects here. For the Linkin Park song, see Iridescent (song).
Iridescence (also known as goniochromism) is generally known as the property of certain surfaces that appear to change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, butterfly wings and sea shells.
3.1 Arthropods and mollusks,
3.3 Minerals and compounds,
4 See also,
6 External links,
Further information: Structural coloration
Iridescence is an optical phenomenon of surfaces in which hue changes in correspondence with the angle from which a surface is viewed.
Iridescence is often caused by multiple reflections from two or more semi-transparent surfaces in which phase shift and interference of the reflections modulates the incidental light (by amplifying or attenuating some frequencies more than others). This process, termed thin-film interference, is the functional analog of selective wavelength attenuation as seen with the Fabry-Pérot interferometer.
In biological (and biomimetic) uses, colours are traditionally produced with pigments, so colours produced other than by pigment are called structural coloration. The use of often multilayered microstructures usually also produces iridescence, as quite elaborate arrangements are needed to avoid reflecting different colours in different directions. Structural coloration has been understood in general terms since Robert Hooke's 1665 book Micrographia.
The word iridescence is derived in part from the Greek word ἶρις îris (gen. ἴριδος íridos), meaning rainbow, which in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and acted as a messenger of the gods. Goniochromism is derived from the Greek words gonia, meaning angle, and chroma, meaning color.
Arthropods and mollusks:
A female golden stag beetle has an iridescent exoskeleton
A Morpho didius butterfly has iridescent wings
The iridescent inside surface of a Paua shell
The wings of Tachinid fly demonstrate iridescent colors that are due to the surface structures
The feathers of some birds, such as kingfishers, hummingbirds, parrots, crows, ravens, starlings, grackles, ducks, and peacocks are often iridescent. A single iridescent species of gecko, Cnemaspis kolhapurensis, was identified in India in 2009. The tapetum lucidum, present in the eyes of many vertebrates, may also be iridescent.
A peacock has iridescent tail feathers
A catfish with iridescent scales
Rainbow boas get their name from the iridescence of their scales.
Minerals and compounds:
Ammolite is a gemstone consisting of iridescent ammonite fossils.
A bismuth crystal with a thin superficial iridescent layer of bismuth oxide
Goethite, an iron(III) oxide-hydroxide, is occasionally iridescent, as in this specimen from Polk County, Arkansas.
Iridescence in an engine oil spill.
Some clouds exhibit cloud iridescence
Rarely, plants are iridescent; for example, the blue-ish leaves of Selaginella willdenowii, Selaginella uncinata (pictured; iridescence not readily visible), and Microsorum thailandicum.
pearlescent paints or interference pigments sometimes used for custom paint jobs on cars exhibit iridescence.
Soap bubbles exhibit iridescence
Compact discs often exhibit iridescence
Nanocellulose is sometimes iridescent as well. Gasoline and some other hydrocarbons and alcohols are often iridescent when floating on water in a thin film.