It took my breath away! Laurie told me it was caused by ice crystals and that's right. So much magic in a little ice crystal or two? I promise myself I will examining the moon every night She is visible to see what else she might want to share with me.
There are coronas, pillars, halos and rainbows that she sometimes displays as well as rings.
See Keith Cooley's moon page with lots of interesting stuff by clicking the link above. (Ring around Moon)