As Roger and I were walking along the frozen creek we were (duh!) throwing rocks to break ice, stomping on the ice, and generally checking out all the neat patterns that naturally occur (including the ice lens and another post that will highlight the amazing fractals that occur naturally).
When looking closely at some of the cracks, I noticed rainbows. Rainbows everywhere! They were typically formed right along the cracks and I had assumed they were the result of stress in the ice.
I’m not smart enough to grok the Wikipedia entry entirely, but armed with that, I was able to search for other discussions.
Here is someone who ran across them in their backyard and did a bit of research.
And here is a whole discussion of the phenomena with lots of studio photos.
The photos at the left are two photos of the same spot. The top photo is focused on the surface and the bottom is focused on the plane of the rainbow.
I may add some more photos if I happen to see some neat patterns. Because, clearly, more ice shall be broken.