User blog comment:Gusdavidson/Episode 6/@comment-23784953-20130822235329/@comment-4773581-20130823002625

From what I gathered, Dust is the (probably natural) resource that can be refined, powdered, and probably messed with in other ways too, and then utilized in various ways to create various effects based on color and refinement level, as seen with Myrtenaster's different barrels, while Aura is basically Qi, a spiritual energy utilized in more physical ways than magic.