User blog comment:Deafro/Theory on Dust Manufacturing/@comment-4773581-20140112153919/@comment-4773581-20140112164222

Aura, the manifestation of one's soul, replenishes because one's soul is still intact, and it doesn't venture far from one's body because that is where one's soul is. To do what you are suggesting would require complete and total removal from the body, which would involve ripping out a part of someone's soul.

Lightning would either involve venturing into an area plagued by lightning while holding an item meant to absorb said lightning, which would basically make creating lightning dust the single most dangerous and nerve-wracking procedure in the entire refining process, or just sticking it somewhere during a storm and seeing if it gets hit. Neither of which are very practical, and both of which would be set off if left exposed to the elements that made them for too long after completion, which would be an extremely common occurance in both cases. The same goes for the other dusts, but especially kinetic and fire varieties. While the crystals may be much more stable than the powder, overexposure to their element, or anything that would agitate them severely enough, would set them off. And from there it'd just be a chain reaction of energies (or the lack thereof, in the case of ice dust). And all of this is furthered with the implied lack of technology at the time.