A peacock’s train (a peacock’s tail) fanning out its elongated upper tail coverts with its shimmering blue or green plumage is perhaps one of the most dazzling sights.
Or the brilliant colored reflections with flash of red on a hummingbird’s throat, and more to the common sight of a child blowing soap bubbles in a garden.
These are all attributed to the phenomena called iridescence.
Iridescence phenomena is exhibited in fine pearls, fire agate, ammonite and iris agate.
This phenomena is caused by light passing through several thin layers on the gems.
Fire agate is a botryoidal form of chalcedony, which looks like clusters of grapes. Hence, the phenomena colors are found in the nooks and small corners of the gem.
Ammonite is a fossilized shell whose original mineral content has been replaced by calcite or pyrite. The iridescence colors of ammonite is a very thin layer which is layered below with an opaque greyish brown.