Endon's Silver Mold (or Curious Silver Mold if it was retrieved before the quest) is a quest item for the Thieves' Guild quest "Silver Lining." Endon requests that the Dragonborn retrieve the mold for him as it was robbed from a Khajiit Caravan by Rigel Strong-Arm and her group of bandits on its way to Markarth. Since it is a quest item, it can not be dropped or stored in a container.