Ithilthum, Valley of the Moon
It is a single map with a small island in the center covered by poisonous water. Once you reach the center, you can use the scroll to summon Limmir. The jeweler will rush to the center, which will trigger waves of enemies to come at you. The enemies all come from the top right, while the jeweler will hide behind the rock. See the quest page, Lost Knowledge, for details.
After the fight, you can make a special amulet by giving the jeweler an amulet, two gems and 1000 gold. Note: except for the amulet's tier, properties on the amulet provided have no influence on the amulet produced.