The mithril hatchet is a hatchet stronger than the black hatchet, yet weaker than the adamant hatchet. Like all mithril weapons, it requires 30 Attack to wield. It can be used in combat or in Woodcutting to cut trees. 21 Woodcutting is required to cut trees with it.
A mithril hatchet is required in the Animal Magnetism quest, in which it is combined with a holy symbol and becomes a blessed hatchet. Blessing a hatchet gives it a prayer bonus of +2.