From the Empowered Sword of Lost Light (Quest) introduced in Unfinished Business.

Radiant Mana Infusion on altar at end of Sclavus Tunnels.
Radiant Mana Infusion
Value:
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

Lilly of Glenden Wood doesn't know what to do with that.