From the Radiant Mana Infusion Quest introduced in Unfinished Business.

Radiant Mana Infusion on altar at end of Sclavus Tunnels.
Radiant Mana Infusion
Value:1,500
15 Burden Units
A small glass flask containing a radiant aqua liquid. Perhaps this could be used to further empower items already infused with great power.


Special Properties: Attuned, Bonded

It looks like you could pour this on some other item.

Notes

You give Lilly of Glenden Wood Radiant Mana Infusion.
Lilly of Glenden Wood tells you, "Now this is an interesting vial indeed! Extreme power is contained within, thank you so much for brining me one."
You've earned 105,999,994 experience.