Crystal Shard

Crystal Shards are a common Hardmode crafting material found in the Underground Hallow, where they grow on Pearlstone Blocks and Pink Ice Blocks. In the mobile version, it is possible to receive them as a rare drop from Arch Demons, while in Pre-Hardmode. They respawn randomly on Pearlstone and Pink Ice blocks in the Cavern layer and below, making farming possible. They emit a small glow, similar to Demonite Ore and Crimtane Ore.

Crystal Shards are also placeable in nearly any position (on walls, floors, and ceilings), though they are not nearly luminous enough to replace other light sources, and placement has no other functional effect. Although new Crystal Shards will only spawn on Pearlstone blocks in the Cavern layer, once harvested they can be placed anywhere. Crystal Shards will not spread Hallow on their own.

Crafting all items, including only one color of Phasesaber, but excluding Crystal Bullets, Greater Healing Potions, and Super Mana Potions requires 105 Crystal Shards. Factor in 250 Crystal Shards for all the other Phasesaber colors, three Crystal Shards for the Super Mana Potion, one Crystal Shard for the Greater Healing Potion, and one per 50 Musket Balls for 50 Crystal Bullets.

Tips

 * Crystal Shards have an unusually high sell value relative to their commonness, so farming them can be one of the most effective ways of making money throughout Hardmode. A full stack is worth more than.
 * For farming, place single horizontal rows of Pearlstone, separated by three tile-wide gaps for walking and harvesting. The farm must be in the cavern layer or below. It may be worth sealing the farm using an outer frame of Clay Blocks or Wood followed by a three-block gap to prevent Hallow from spreading. Actuators can be used to switch Pearlstone to an inactive state, causing all Crystal Shards to drop for easy harvesting.
 * Crystal Shards emit a glow, so getting rid of light sources makes it much easier to spot them.