Pearlstone can increase the Hallow, and apparently pearlstones bricks in sufficient quantity can as well -- what about pearlstone walls? --Sinister Stairs 16:09, 16 December 2011 (UTC)
- I would _guess_ that the background walls can never affect the presence or absence of Corruption or Hallow, but you're quite welcome to test it and post your results. --Theothersteve7 16:12, 16 December 2011 (UTC)
- My testing shows that a large room of Pearlstone Brick does not cause Hallow. Wizarth 11:26, 23 December 2011 (UTC)