Moonrock Ore Shard

Moonrock Ore Shard  s can be found while mining Moonrock Boulder at night on most island types. Moonrock Boulder are very common, have a bright neon cyan-colored glow, and can be seen from a great distance at night, but only when the moon is in the sky and lit. Moonrock Boulders are particularly easy to spot on Desert Islands.

Crafting

 * Moonrock Sword
 * Moonrock Ring
 * Moonrock Key

Source

 * Moonrock Boulder