Shroomite Plating

This is a decorative brick and nothing beyond that. It throws off a faint glow where you place it, but the game does not count that as lighting, so a room built entirely out of it still fails the housing check until you hang a lamp somewhere.

The bars behind it are the same ones that build one of the strongest ranged sets in the game, which puts this at the end of the longest crafting chain any block has. A later patch made the ratio much kinder, so it is no longer the extravagance it once was, but you are still turning Chlorophyte into wall texture. Build the armor first and decorate with whatever is left.