Iridescence
Property in which fine colors, changeable with the angle of view or angle of illumination, are produced on a surface by the interference of light that is reflected from both the front and back of a thin film
Iridescence is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstructures or thin films. Examples of iridescence include soap bubbles, feathers, butterfly wings and seashell nacre, and minerals such as opal. Pearlescence is a related effect where some or ... Wikipedia