I took the fractal I used in Storms of Life and played with it, rotating, recoloring, adding layers, etc., and ended up with something that looks rather like a combination between a gravity well and a lightning storm.

This was the result of playing around with gradient overlays and an old Apophysis render that had been calling for me to find a use for it. The jewel is actually the first one I ever designed in 2008 following a tutorial, but for some reason I missed the part about how to add the shine and couldn't figure out why it looked so flat . Three years later I finally revisited it and came up with this.