You must gather 8 Melonfruit and squeeze their juices into the Cup of Elune at Sargeron.
The markings on the Sargeron ruins, combined with what you've gleaned from Furien's text make one thing clear:
There is something special about the old fountain in the Sanctuary of Elune.
It would seem that one could expect special power from washing their face in the fountain. First, of course, there would need to be something in the ancient fountain with which to wash.
Pondering this problem, you spot a melonfruit at the base of a nearby tree....
After filling it with liquid from the melons, you proceed to wash your eyes from the ancient font.
Upon opening your eyes, you are able to see the spirits of ancient elves, still faithfully carrying out rituals to their goddess.
You ponder the significance of this revelation and determine to study Furien's research for more clues....
Upon completion of this quest you will gain: