Fusing together redstone and glowstone results in Nitor, a seemingly eternal and sourceless flame. It forms an important part in the creation of Runic Essences.
Nitor can be placed in the world as a everlasting light source, like a torch You can place it anywhere (i think) and even underwater! It has an additional strange property - it seems to contain more Vis than went into it's creation.
You can fuse nitor and alumentum, which is made by fusing coal and redstone, in an infuser to make an arcane singularity which can be used for various things.