Iridescence
Iridescence is a thing about some surfaces. If a surface looks like its colour changes as the light moves, then it is iridescent.
There are many iridescent things in nature. Soap bubbles, butterfly wings and sea shells, and some minerals are iridescent. They have tiny structures that affect the light.
The physical process which causes iridescence is usually interference.
Iridescence Media
Fuel on top of water creates a thin film, which interferes with the light, producing different colours. The different bands represent different thicknesses in the film. This phenomenon is known as thin-film interference.
An iridescent biofilm on the surface of a fish tank diffracts the reflected light, displaying the entire spectrum of colours. Red is seen from longer angles of incidence than blue.
The pearlescent shell of a black-lip pearl oyster
Cornell drawer displaying iridescent insects
Structurally coloured wings of Morpho didius
The inside surface of Haliotis iris, the paua shell
Both the body and the train of the peacock are iridescent
A Neon Tetra in a Community Tank
