Anguish Gemstone

There are four types of Anguish Gemstones:
 * Titan Gemstone
 * Torment Gemstone
 * Margonite Gemstone
 * Stygian Gemstone

Acquisition
They drop rarely as loot from the monsters in the Domain of Anguish. One gem of each type is also available as part of the reward for completing the Mallyx the Unyielding quest.

Uses

 * Four Anguish Gemstones (one of each type) must be traded to Keeper Millzesh in Abaddon's Gate in order to complete the Finding a Purpose quest and recruit Razah in PvE.
 * Four Anguish Gemstones (one of each type) can be traded to the Keeper of Secrets in Gate of Anguish for a Coffer of Whispers.
 * 100 Anguish Gemstones (25 of each type) can be traded to the Spirit of Truth in the City of Torc'qua for an Armbrace of Truth, which can be traded to the Deacon of Whispers for a gold tormented item.