Cooling lava, where only a very thin layer of hardened rock is covering the still molten stone.
Don't know if this is ok, as its using emission.

OK, I now see the preview, there is no emission visible, so I think this material should be deleted, as its not really interesting now ( totally cooled off .. :) )

Hehe, put it in as a template for further use in spite of cooled, renamed it in this sense :)

still looks cool :)