Talk:The Hallow/@comment-4699258-20120111100702/@comment-4744632-20120112194937

While hallowed/corrupted stone/sand won't convert each other, hallowed grass can take over corrupt grass, and vice versa, and seems to do so randomly (though the corruption seems to be stronger). If you want to prevent the spread of either side you can build a 3 block wide wall of blocks which can't be converted, such as wood or bricks, or create a gap between the blocks (such as a hellevator) which will stop the spread of hallow or corruption. If you build a wall though, it’ll be harder for corruptors to spread corruption.