Ebonstone Block

Ebonstone is a rock that can only be destroyed with higher tier pickaxes (Nightmare Pickaxe and Molten Pickaxe) or Dynamite.

You can turn it into normal stone with Purification Powder.

Devourers will spawn anywhere where there is Ebonstone. For this reason Ebonstone is a good way to make a harvester for Devourers. Also because of this reason, making a house out of Ebonstone is not advised.

Clearly, there is Ebonstone wall but it can't be item and be crafted. the fact get in the way of building made into Ebonstone.

As of patch 1.0.5, Deathweed can grow randomly on Ebonstone blocks.