Quote Originally Posted by Alleluia View Post
I agree its an oil allegory, but doesn't south Garlemald/Camp Broken Glass's sidequests mention its specifically water soluble? The extractor is extracting it from the ice (and you can often see a blue tint on the ice on the lake) or the lake water below it. Oil is not water-soluble, so ceruleum's actual form likely isn't oil-based. It seems almost more like heavy water to me.
They drill it from beneath the lake. From what I understood, the parts of it in the ice itself are where it escaped/leaked, became unstable, and then exploded. Both the Garleans and the Ul’dahns drill for ceruleum in Thanalan, which famously lacks water.

With the writers also describing that it’s dug up from the ground and made up of ancient life, as well as the fact it needs to be refined, it’s just a fantasy version of oil that has absorbed aether. A Gridanian NPC even refers to it specifically as oil.

The most important attribute of ceruleum though, is being fantastical and fictional, it can be used for whatever purpose the writers need it for. From powering magitek, to heating homes, to being coated on relic weapons.