The gold helmet is a helmet the player must smith during the Between a Rock... quest using 3 gold bars. It requires level 30 Defence to wear. Smithing the helmet requires 50 Smithing and gives 30 Smithing experience. More than one helmet can be made by using the drop trick and casting Telekinetic Grab on any helmets dropped on the ground. The helmet must be worn to use Dondakan's cannon and to enter the massive Arzinian Mines, found in the mines south of Keldagrim.
During the quest, once in the mines, the helmet will begin to get heavy. Because of this, a player may only stay in the mines for eight minutes before the helmet becomes so heavy that they are magically forced out. After the quest, the helmet will not force players out, although it must still be worn to enter the mines. It is the heaviest piece of equipment in the game. Entering the mine after completing the quest unlocks the In Between song.
To leave the mines, a player must remove the helmet. When this is done, they will automatically be teleported outside. This costs the player one inventory space, so some players log out instead; if a player logs out in the mines, they will automatically be teleported outside.
To make the helmet after the quest, have 3 gold bars and a hammer in your inventory and smith it on any anvil (option won't be available if you have one in your bank already).