Talk:The Underground/@comment-26602680-20150708191000/@comment-25211243-20151004202710

It's just background material. It doesn't do anything and I don't think it can be collected. It can also be in blue and red possibly representing the Hallow and the Crimson, so it may be something to do with them. I've found all of the colours in a world with just Corrpution and a different world with just Crimson, so I don't think the colour can tell you which biome you have in the world.