This is the composite version of the gem diffraction, although this is only my rough draft, upon 69 downloads I will be posting a more efficient way to do this effect. NOTE: this effect does not work in all types of light so be careful. You can easily turn up the color effect in the compositor or contact me for help.
Yeah sorry I was unsure as to if I should put it under low poly or not. But recently I have found yet another way or two to use composting and material textures to make light defraction. Although if you really want accurate results you should use yafaray and its photons. There are a few totuorials online.