If you looked up at the sun Monday (hopefully with proper protection), you probably saw a rainbow around the sun. It's also known as a 22 degree halo, or sun halo.
According to ABC Action News Meteorologist Denis Phillips, a 22° halo is caused by tiny ice crystals contained in high cirrostratus clouds. The sunlight (or moonlight) REFRACTS through the ice at a 22 degree angle.
Phillips added that the halo is a common event.
Do you have a photo of the ring? Send it to email@example.com