The diamond door is the second highest tier of doors. Players can toggle them to be opened or closed by hitting it. Only the person that placed the door and teammates can use it. Diamond doors have much more health than wooden doors, stone doors, and golden doors.
Having multiple doors in a base can help as they enable players to enter and exit the base with convenience.
Any amethyst tool or hammer can break the diamond door if used long enough. Normal tools are not able to break the diamond door.