Nacreous clouds

Nacreous clouds
（真珠の様な色をした雲）

Photographed over Antarctica, the rare nacreous cloud is made up of millions of ice crystals which bend and scatter the sun's rays, creating a pastel rainbow.
From the Daily Mail

The great 31st January 2005 display over Scandinavia as seen from Oslo. The clouds were visible before dawn and throughout the day. Here is their evening appearance imaged by Arne Danielsen
From Nacreous clouds

These clouds blazed in the sky over the Southern Norway twenty minutes after sunset January 31st 2005. Imaged by Derick Rethans (site). The clouds were visible before dawn and throughout the day and evening.
From Nacreous clouds