Iridescence is a shimmering, rainbow-like quality where colors seem to shift and change as you move or as light hits a surface from different angles. A soap bubble floating through the air shows iridescence: one moment it gleams purple and green, the next moment pink and gold, all without anyone adding new colors.

Many things in nature display iridescence. Hummingbird feathers flash brilliant greens and reds as the bird hovers and turns. Peacock tail feathers shimmer with blues and greens that seem almost impossibly bright. Butterfly wings, some beetle shells, and even oil slicks on water all show this effect. The colors aren't from pigment, like paint on a wall. Instead, they come from the way light bounces off microscopic structures on the surface, bending and reflecting in ways that create those shifting, magical colors.

When something is iridescent, it has that same rainbow-like quality: colors that seem alive, moving, and almost impossible to pin down to just one shade. A dress made from iridescent fabric might look blue in bright light but shift to purple in shadow.