This quest is part of the quest On the Shores of Freemarch.
In the northeast hallway of Iron Tomb is a short cross hallway, going no more than 30' to east and west, which crosses the main hallway. In the east branch is the Curious Endless Idol to update this quest.
You will have to turn it back in to Uriel in Meridian. The last step is to activate the nearby empty table to "examine" the item. This is the table by the stairs down.