Soul Chamber

Soul Chambers are brilliant, but fragile gems that can be used to imprison demons. The crystals may be shiny, but they're also deadly. If they are damaged in any way, the demons trapped within may escape.

Soulkeeper Uriah and Apprentice Rosalyn were in possession of a handful of Soul Chambers, which they were to transport to Allari the Souleater in Azsuna, but while traveling through Mucksnout Den their caravan was attacked and ransacked by kobolds, who are now in possession of the gems.

Source
This item drops from Mucksnout Aggressors, Mucksnout Collectors, Mucksnout Hoarders or Mucksnout Scavengers throughout the Mucksnout Den.

Objective of
7 of them need to be acquired for Shiny, But Deadly.