Board Thread:Speculation House/@comment-70.72.38.180-20150401032633/@comment-4010415-20150428204623

I'm not sure that Dust can be found combined, since the narrator said that the four main types are the naturally-occurring ones. This would imply that the mixed types must be mixed through some kind of interaction that humans purposely trigger or something.

And considering how the Ruby sneeze scene went, I'm inclined to believe that Dust doesn't just combine by being around other colors or activated at the same time as other colors. The red, dark blue, and yellow Dust she sneezed on had separate effects - fire, ice, and electricity - rather than combining into one or two effects.