From the Elemental Weeping Weapons quest introduced in the Visions In The Darkness event.

Freezing Elemental Pool
Freezing Elemental Pool
Value: ???
Unknown Burden
An elemental pool, nearly frozen over.

You examine the elemental pool, being careful not to get too close.

You give Freezing Elemental Pool <Weeping Weapon>.
<Character Name> submerges the Weeping weapon in the freezing pool. The weapon takes on the elemental power of frost!