Cool, but not exactly what I saw—it was literally a *rainbow* completely circling/ringing around the sun—didn’t last long, but it was so neat to see! Those were the days before cell phone cameras, or else I’d have a pic to remember it by! :-)
A complete raindow around the sun is called a 'Rand's Rainbow. The pictures below are of a 'Circumhorizontal Arc'. These don't ring the sun but look more like a very wide upside-down rainbow. The pics don't do it justice - it was very vivid! These were taken 06-03-06, Spokane WA, looking south.
This will be a killer for slow connections (I did shrink these quite a bit) but here goes...