It is in a locked display case along with two more Grand Soul Gems that are not empty.
With the exception of Skingrad, the merchant in each city's Mages Guild has one which can either be bought or pickpocketed.Calindil at the Mystic Emporium in the Market District has one, which can be bought or pickpocketed.Mostly you have to find them while adventuring, but starting this quest places 3 of them in nearby dungeons which would have been previously unavailable prior to starting the Vampire Cure quest.įrom the Wiki page, places that always have an empty Grand Soul Gem: The walkthrough for the Vampire Cure quest on the UESP Wiki gives locations.
