I’ve got an idea for a new material: Black Metal. It is on the same level as gems, but has no element. It deals slightly more damage to elemental enemies, and ever-so-slightly less damage to normal (physical) enemies.
This could provide an opportunity for 1 or more new worlds: T5 and above metal worlds, where rough black metal can be found! Compact black metal might make for a nice industrial/grimey look.
The color of steel here is what I’m invisioning when refined:
(Sorry for low res, it’s the best I could find on Google haha)
It could also be used to craft new decorative blocks that look more grimy, like a steam/smoke vent and maybe a soot block?
I really like the idea of rock polishing/shining (as I’m into that irl haha)! That might be a totally different suggestion though, like maybe a new tumbler machine that you put boulders/rock towers into for a nice polish?
There was discussion around the possibility of painting metals back when goo farming was first introduced and if I do recall correctly even James was part of the discussion trying to figure out how it could be implemented best.