shimmer is a metallic binder with PC's to color/tint it to the desired results... looks very blingy but without the hard feel of glitter... and you can hold some killer detail with it.
If I was to make a guess it would be a like a .002 particle size vs .008 or so for glitter.
we tint it all the time to pinks, fl purple, copper, golds, etc. -- we generally will find a pantone color and use it for the pigment formulation and then tweak from there if we're trying to hit a specific color.
We've been using Matsui Metallic binder for a while now and it's been great.