From The Aetherium Wars
Modern scholars know Aetherium as a rare, luminescent blue crystal found in some Dwemer ruins. Most consider it little more than a curiosity, as it has proven all but impossible to work with: while it has a strong magical aura, it is alchemically inert, and no known process can enchant, smelt, mold, bind, or break it.
To the dwarves, of course, such problems were merely a challenge. In the years following King Harald's reign, the Dwemer discovered a considerable source of Aetherium in their deepest delvings. An alliance of four cities, led by Arkngthamz, the great research center in the southern Reach, was formed to oversee its extraction, processing, and study, and a new 'Aetherium Forge' constructed to smelt it under precisely controlled conditions.
From Caluurion's Notes
Emptying them out, I discovered a significant quantity of an unknown material: raw chunks of vibrant blue crystal that give off their own light. They'll receive closer examination once I've sealed the remaining perishable Dragon parts in the emptied containers. I take a certain gratification in the irony that these treasure chests will soon mostly contain the Dragon itself.
The crystals are useless. To call them inert is an understatement. They are the essence of stasis. Unchanging and unalterable. I can safely put their study aside indefinitely.
And of course, according to Neramo
Fang Lair's original name was Arkngthamz
-Phng...thoughts? I'm wondering now if Fang Lair was
that 'considerable source of Aetherium' (the timing seems to be about right, with King Harald wiping out the last of the Dragon Cult and Caluurion calling Thurvokun, 'the last of its kind, or near enough to make no difference') and the Dwemer would then have fallen into their civil war over the stuff because Thurvokun decided to sit on their stockpile...
PAWS (Positively Against Wrip-off Stuff) - Say No to Crown Crates!
A useful explanation for how RNG works