Excerpt from ‘The history of Coerthas, from refuge to Holy See’ by Archon Niniri Niri.
Aurum Vale has long attracted miners and prospectors from across Aldenard due to rumors that it contained massive mithril veins. Unfortunately for the miners the rumors were incorrect, and the caves instead contained goldbile, an utterly deadly substance that gradually cooks the lungs of those who breathe its fumes, as well as corroding flesh on contact. This liquid is a fusion of mithril, sulphur and groundwater. To add even more danger to the situation the goldbile had mutated a number of the beasts within, strengthening them and making them more ferocious. This was causing a severe issue for Ishgard as the beasts were emerging from the cave to maraud across Coerthas, and so they requested assistance from the Grand Companies of Eorzea, who dispatched adventurers to the Vale to cleanse it in exchange for several battle-trained chocobo.
The Vale opens in a narrow corridor of rock occupied with vegetation and bioluminescent fungus nicknamed the trap by those who survived the Vale, likely due to the danger of the caves beyond.
The Golden Pools
The Golden Pools of Aurum Vale are an area with an intense concentration of goldbile, the same substance that has claimed the lives of so many miners.
Further within the caverns, the naming scheme bitterly coined in irony by the survivors of the caves can be found to begin. This scheme concerns mainly references to themes of monetary and banking matters, allusions to the wealth foreseen by those prospectors that came to the Vale and died there. In this case, the lock blocks the way to the further depths of the Vale.
The Banded Lid
This region of the Vale was undeniably the breeding chamber of the morbols of the Vale, though thankfully their vile progeny were quashed by the adventurers before the team arrived there. The name of the area is reference to the lid of chests and similar containers, typically made of wood banded with strips of iron to reinforce the structure. Thus, this is a further defense for the inner Vale in the mind of those who explored it.
The Empty Pocket
A small, peaceful area of the Vale, this short corridor is entirely free of goldbile and the hostile flora of the caves.
The Coincounter’s Chest
As in reality so in the Vale, the chest lies beneath its banded lid. In this case the chest did not seem to contain any particularly valuable goods, merely the toxic emissions of subterranean goldbile geysers.
The Miser’s Hold
Yet another breeding hold of the vile morbols, this area was reportedly home to not only large clutches of morbol fruits and their mature guardians. The Miser is a representation of the fatal grip of the Vale, and so this is his personal domain.
The Miser’s Take
Within an area known as the Bile Lake, a region of immense subterranean supplies of goldbile, the Miser’s Take was perhaps more rife with the caustic liquid than any other area within the Vale. Apparently the most junior of the morbol fruit were growing here upon the Vale’s cleansing, still in the edible and curative form of their earlier stages. The ‘take’ referenced was likely the cost of life incurred by the Vale upon those who explored it.