The bone shard is a quest item that is given to the player by the Spirit of Zadimus during the Shilo Village quest. When the player buries the corpse of Zadimus next to the tribal totem in Tai Bwo Wannai, Zadimus's spirit appears and thanks the player. The bone shard then emerges from the soil.
If the shard is lost for any reason, players will have to retrieve Zadimus' corpse from the temple (rumoured to be Ah Za Rhoon) and bury it again.
The shard is used later in the quest, when the player must fashion it into a Bone key using a chisel in order to enter Rashiliya's tomb.