User blog comment:Zathronas/Speculative author, Volume 3: Cinder Fall/@comment-10380701-20141203030157/@comment-4010415-20141203170508

I'm still trying to figure out if there are two different types of orange Dust because of that box. It looks like one group of those orange Dust crystals is brighter than the other group. Like, the four on the left are red-orange and the four on the right are bright orange.

We already know that there exists blue and cyan Dust. The ones on the left are blue, and the ones on the right are cyan.

I think we can actually safely assume that the four naturally-occurring Dust colors are red, blue, yellow, and green. Blue, not cyan. It's likely that blue is the one that produces ice, since the Dust that Ruby sneezed on in The Shining Beacon was a collection of red, yellow, and dark blue Dust, resulting in fire, lightning, and ice.