The rod clay mould is an item first made by the player during the In Aid of the Myreque quest to craft the silvthrill rod, which later becomes the Rod of Ivandis. It can still be used to create silvthrill rods after completing the quest.
It is made by using a piece of soft clay on the tomb of Ivandis Seergaze, under the Hair of the Dog pub in Canifis. After entering the basement of the pub, the tomb is located in the first cave entrance after walking through the secret door. The player can repeat this after the quest to create a new mould, should they lose the one they made during the quest.