User blog comment:ChishioKunrin/Dust: Fire! Water! Lightning! Energy?/@comment-2135507-20140822065804/@comment-4010415-20140823122513

^ I agree with Maki. That's certainly what it looked like. Yellow + Glyph = Haste glyph. Kind of like how Weiss had the blue (water/ice) Dust in Myrtenaster lined up with the weapon's exhaust port when she put glyphs in front of Crescent Rose. She must've used blue Dust with her glyphs to coat Ruby's bullets.

So, when she uses Dust with her glyphs, it can make some pretty spectacular effects and look pretty cool.

I assume that Weiss' glyphs normally just move things, so whenever they're doing something different, she's influencing them with Dust.