White Auracite, from my understand, is just really good short term storage device for Aether, but it doesn't hold it for long. Think of it like a battery that you can fill up with a ton of electricity, but it only holds the charge for a small amount of time. It works by containing the Ascian in their pure Aetheric form, this allows for the Ascian to keep trapped (Unable to go back to where ever ascians hide away to regenerate) long enough for a massive burst of aether to basically whether down what would be an Ascian into just small aether chunks that have nothing to do with the previous Ascian. For an analogy, think of a rock. Now imagine that rock (The Ascians soul) is blasted with high pressured water (The massive aether burst) to whether it down til it just begins minute grains of sand (Aether). The rock is unable to reform and it's now just a bunch of sand.