Ancient Riddle Box

The Ancient Riddle Box is a quest-related fishable which has a chance to be obtained from fishing in the deep Ocean, according to the book, Amulet Locations Text. It can be crafted with 1 Moonrock Ore Shard to get the rare necklace Mind of Stone.

Source

 * Fishing in deep sea

Trivia

 * The ancient riddle box can also be found when fishing in shallow water. It is not known if this is a bug.