I was out looking for more thorium and went down a hole I found between an Azure Forest and some ice. There was no ~~thorium~~ cobalt to be found, so I started to dig up out of the cave system. I encountered some tam blocks, sandstone maybe, and copper. I was unable to mine either. I tried with my ~~thorium~~ cobalt pickaxe, as well as a crude pickaxe I had found.

They show no signs of being struck. Also the bald head is gone again.