I recently heard a tip that in the mobile version of Terraria, illuminant slimes and bats spawn much more frequently in the underground hallow, obstructing the spawn of Chaos Elementals. I was wondering, if I built a large, enclosed area of pearl stone on the surface, would Chaos Elementals spawn? And if not, what is the best way to farm them in the mobile version of Terraria? I have attempted to place pearl stone blocks in a line in the jungle, but all that spawns is pixies and illuminant bats.
A quick Google Search shows that Chaos Elementals spawn in the Underground Hallow. That same page also advices
On the Mobile version, Illuminant Bats and Illuminant Slimes are overabundant in the Underground Hallow, and will block nearly all Chaos Elemental spawns. This can be alleviated by making an area of Pearlstone or Pearlsand outside of the Underground Hallow, so Chaos Elementals can spawn unobstructed.
This works because
Chaos Elementals will only spawn on top of Pearlstone or Pearlsand Blocks. They can do so even if the player is not specifically in a hallowed biome.