Dark Shard

The Dark Shard is a Hardmode crafting material used in the crafting of the Dao of Pow and the Onyx Blaster. It has a 1/10 (10%) chance of being dropped by Dark Mummies in Corrupt Deserts, Blood Mummies in Crimson Deserts, and Shadow Mummies  in Corrupted Deserts.

On the, they also have a 1/15 (6.67%) chance to drop from Tainted/Vile Ghouls which respectively spawn within the Crimson/Corrupted Underground Desert, and a 1/25 (4%) chance of dropping from Bone Biters and Flesh Reavers.

The Hallow counterpart is the Light Shard.

Trivia

 * The Dark Shard represents the "Yin" of "Yin Yang" or Taijitu on the Dao of Pow.
 * The Dark Shard and Light Shard don't actually create a circle when put together, instead it is a circular shape with a couple pixels missing