Ice crystal mechanic

I think it'd be interesting if the ice crystal could amplify or 'carry' light across gaps. Like placing them every few blocks with a torch at the end would carry the light level of the torch through every crystal. (mabey with diminishing returns to not make it too crazy) 

This would also create some fun interactions with the icicles falling down in the ice caves.

It would also belong alongside the amethyst crystal which carries sound while the ice crystal carries light.