i've always been fascinated by iridescence. check out these pics and some of the websites that contributed to this post!
"...the phenomenon occurs due to the interference of light through multiple reflections within the structure of a material."
"Most of the creatures famous for their beautiful coloring, such as peacocks, butterflies, and Japanese beetles, achieve such ornate patterns through reflections from iridescent structures rather than pigments, a common misconception."
if ya wanna get all science-y about it...
