User blog comment:Waters Knight/Monty Tweets About 'Dust Levels'?/@comment-5054402-20140514145150

Well, dust is a kind of natural mineral on remnant and comes in the form of a crystal and either cut into a gem shape or ground up into dust. I wouldn't say they have a "power level" per-say, but, each kind of dust has it's own little power/ability/effect being told by the dust's color.

And aura, like Jaune said, is pretty much a force field whenever you choose to use it. Or if you want to get more complicated, "Aura is the manifestation of our soul. It bears our burdens and shields our hearts."

And for semblances, they are just an ability that a lot of people seem to have. It's sort of like a unique super power, I guess. Although, not everybody has a semblance.