The only way to obtain this item without the use of the console command (
player.additem 039d4a) is with a reverse pickpocket. After completing the main quest line of The Elder Scrolls V: Dragonborn, Frea becomes available as a follower. Give her another amulet and make sure that she equips it. Then send her home and pickpocket the amulet from her. However, this may not always work.