Iridescence is a shiny, glowing quality. The bright, colorful surface of a soap bubble is beautiful because of its iridescence.
Aside from the soapy bubbles you can blow and watch sailing away in the air, certain seashells and butterfly wings also have the property of iridescence. The iridescence of an oyster or abalone shell lining is called "mother of pearl," and a pearl is a gem that also has iridescence. This noun comes from the adjective iridescent, which originally meant "rainbow-colored," from the Latin root iris, "rainbow."