Bone

Bone is a crafting material mainly used to make armor and weapons. It is dropped by Skeletons in the Deep Caves.

Bones are a basic early-game resource once the Deep Caves are reached, and they are primarily valuable as a component in combat-oriented crafting. Because they come from Skeletons, gathering them is tied to exploring cave areas and fighting undead enemies rather than farming or processing other materials.

In practice, Bone is most important for players who want to progress through gear recipes that rely on monster drops. Since it is a crafting material, it should be saved rather than sold or discarded if you are planning to make armor or weapons that use it.