Elder rune burial longsword is a piece of burial equipment that can be made at a Burial Forge and Anvil. Making this item consumes a elder rune longsword + 5 to make the in progress smithing object. Once the progress on the object has been completed, the item is immediately removed from your inventory. This effectively functions as 'no reward high experience' method.
Burial items grant the same amount of experience as the final upgrade of that item. This effectively doubles the experience per item if a burial item is made from a +4 item, or a 26.6% increase if the burial item is made from bars.
This information has been compiled as part of the update history project. Some updates may not be included - see here for how to help out!