Iridescence

Iridescence in soap bubbles

The iridescent exoskeleton of a golden stag beetle

Iridescence is a physical property of some surfaces. Their colour appears to change as the angle of view or illumination changes.

Examples of natural iridescence are common. It can be seen in soap bubbles, butterfly wings and sea shells, and certain minerals. These are structural colours caused by microstructures which interfere with light.

The physical process which causes iridescence is usually interference.