Cloud iridescence is the occurrence of colors in a cloud similar to those seen in oil films on puddles, located in the general vicinity of the sun or moon. It is a fairly common phenomenon, most often observed in altocumulus, cirrocumulus, lenticular clouds and cirrus clouds.
That is research to satisfy my mind after seeing my own spectacular view this morning. I was almost home from the laundromat but I didn't have the camera with me when I first saw a massive "rainbow" cloud that was completely encircled with all the colors! When I arrived back home 3 minutes later I took the photos below. They will give you an idea of what I saw on the trip home. The most beautiful one was gone, but these are kinda pretty, anyway.