Moonstone

Obtained by Xerevies Vara'nel from the heart of Darnassus, a potent moonstone powers the defenses of the Fireborne's underground facilities nestled deep within the bowels of Uldum.

It is believed that Elune's Gem, a massive amethyst pulled from a shrine within the Ruins of Eldarath during the Fireborne's time within Azshara, may possess similar properties. However, no experimentation has been done on this relic to date.

Functions
The moonstone is responsible for powering the Zenith's most powerful defenses. Feeding off of its energies, the arcanic servitors are able to conjure massive nets of energy which are designed to either ensnare or crush intruders. It also powers a series of blood crystal wards that fire powerful bolts of energy at trespassers within the vaults. Finally, the additional energy has provided C.A.S.I., an arcane elemental conjured and subjugated by Aloridan Tel'thalas, with greater abilities and control over the facilities.