Nacreou cloud
This fantastic colorful nacreous cloud appeared in the sky of Abisco, Sweden on December 14, 2015.

Mother of pearl clouds are a kind of polar stratospheric clouds that float through the stratosphere (25 km above Earth surface) and they are fantastically colorful.

Mother of Pearl cloud
These rare colorful clouds form in the lower stratosphere when temperatures drop to around minus 85ºC. The iridescent colors appearing in the clouds are the result of diffraction and interference of sunlight shining through tiny ice particles ~10µm across.

Nacreous cloud
Nacreous clouds far outshine and have much more vivid colours than ordinary iridescent clouds. However, some polar stratospheric clouds are linked to the destruction of ozone.