Rainbow Cloud

I came across a rare and fantastic sight just a few days ago and was fortunate to have my camera handy. It is most often called a Rainbow Cloud.
















My physics friend informs me this is caused by the cloud encountering cold water vapor and the high noon sun refracting through it just at the right time and right circumstance.
It does seem strange that this was the only cloud that was affected. As you can see the other clouds around it are normal.
Not exactly a space ship so probably not alien visitation.
Sure was nice to look at, perhaps an angelic visitation or sign.
regardless, the cloud existed for almost 15 minutes before the the winds dissolved it. It was able to travel a distance as a rainbow cloud.