Guild of Writers

I've seen in a few ages, such as Eder Delin, and Sonavio, that around some firemarbles, or lights, there's a sort of halo, or sparklie thingie around it that makes it look more realistic as a light. I was wondering, what are these, and is there a tutorial to make them?

They are sprites. The tutorial is here.

Ah... that's what I thought they were called, but when the tutorial started talking about Imagers and stuff, I got confused XD