We saw this double-rainbow one evening this week. This photo has been tweaked a bit so as to help the fainter rainbow show up a little better here.
 At once I was in the Spirit, and behold, a throne stood in heaven, with one seated on the throne.  And he who sat there had the appearance of jasper and carnelian, and around the throne was a rainbow that had the appearance of an emerald. (Revelation 4:2-3 ESV)
That must be some rainbow!