Hallowed Corruption not spawning crystal shards

[DoctorPepper1886]

As the title says, I had the misfourtune of having my Hallow spawn in the Corruption, and have not seen any crystal shards. Do I need to keep waiting, or do crystal shards only spawn in hallow, and not a hallowed mixture?

[Snorgrifflax]

I do know that you will need to wait a while (not sure how long). But if they still dont spawn in the biome you can just move the hallow to a "pure" area. Also i think they might only spawn in the cavern layer.

[Snorgrifflax]

Its possible to farm them with wires. Spawn surface must be pink ice block or pearlstone to grow

[Blargo]

Crystal shards can grow in any biome, provided that the pearlstone blocks are at least at the cavern layer.
Here's the wiki page for the cavern layer depths, they differ depending on the world size:
http://terraria.gamepedia.com/Cavern

[Dani]

Go to the Cavern layer.