Hey Bob,
I too saw that huge ring around the sun here in San Antonio, Tx about one 1/2 months ago.  It was on a Wednesday in mid May.  With my sunglasses on, the ring was a rainbow just as your picture !
 
It made the local news but I don’t think there was an explanation.  We only saw it this one day.
 
Very interesting !
 
Thank you for posting it..
 
P.S.
Would you p.m.  with that picture ?  I would like to show it to some friends !
 
Thanks in advance.
 
Carol Garza