Ebonstone Block

Ebonstone Blocks are the blocks of which Chasms in The Corruption are primarily composed. These blocks encase Shadow Orbs and most Demon Altars. They can only be mined with a Nightmare Pickaxe or higher, Dynamite, and Bombs. Using Purification Powder will turn them into ordinary stone blocks.

Eaters sometimes spawn nearby Ebonstone Block even if you are in a biome besides the The Corruption.

Placing 200 of these blocks causes the current biome to transform into The Corruption or Underground Corruption biome, which will spread and spawn their mobs, such as Eater of Souls and Devourers. This can be used to the player's advantage to make a suitable arena for fighting the Eater of Worlds. Deathweed can grow on Ebonstone.

Once in hardmode, any corrupted block will turn regular stone blocks that are up to three squares away into Ebonstone blocks.