Dave, the light is refracting through one of the crystals, and that is creating the full color spectrum
that you see there. It's an excellent capture of the prism effect, and it's interesting that the ice crystal
was shaped just right to produce the broad color spectrum in your image.
Mike
Thanks for the input. I have several crystals that give a rainbow effect but the length is what I do not understand. I wonder if it is the layers in the ice crystal that give it the repeating effect. Ah, the wonders of nature
And, 'aahh' in awe of those who understand and can explain all these things. Science and maths just went completely over my head in school and I acknowledge how ignorant I am in relation to so many fascinating things that make our world tick.