How can I break the corrupted rock?
I'm in the corruption, and I noticed that the rock here is indestructible. Why?
The block type I'm facing can't be destroyed
That is ebonstone and it can only be broken with higher tier pickaxes.
From your screenshot, it looks like you have either an iron pickaxe or a silver pickaxe, neither of which are strong enough to destroy the ebonstone.
It is possible to destroy before you obtain the higher tier pickaxes using one of these methods: