Board Thread:Speculation House/@comment-14138255-20140822003454/@comment-25308133-20140827032034

It's used as a power supply in most of their technology, which implies that it's base form can be used as a form of energy without aura. That combined with the fact that it's apparently unstable, much in the way that nitroglycerin is, then something in the sharp motion Ruby did when she sneezed, or in the movement in the air caused by said sneeze triggered it. Alternatively, the sneeze may have caused a small involuntary pulse in Ruby's aura that set it off.

In terms of the interaction between aura and dust, I assume, and this is just a theory, that for any complex directed effects you need to use aura to shape and control the release of the energy. In otherwords you don't need aura to activate dust, just to control it in any way other then the most primitive.