Iridescence

Iridescence in soap bubbles

The iridescent exoskeleton of a golden stag beetle

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.