Adamant Hatchet is stronger than Mithril Hatchet. It can be used for combat or to cut down trees. It requires an Attack level of 30 to be equipped, and a Woodcutting level of 31 to be used. It can be bought from Bob east of ::home for 1,280 coins.
Adamant Hatchet can be made with the Smithing skill at level 71 using one bar.