Difference in PBT keycaps?

[KaminKevCrew]

Hello  

I bought two different sets of keycaps from massdrop recently. One is the keycool blue to white fade set (In PBT) the other is the vortex backlit Double-Shot PBT keycaps in white. I've noticed that the keycool ones have a very rough texture, but the vortex ones have a very smooth, silky feel. Almost like a quality, plasticky version of the aluminum finish on macbooks. 

Is it really possible for pure PBT to have these differences in texture, or is there something wonky going on?

[FatalityDiablo]

http://de.wikipedia.org/wiki/Polybutylenterephthalatthere is no difference in metrial other than a different dye, but rather in the process of Extrusion http://en.wikipedia.org/wiki/Extrusion#Die_design using a textured key-cap (I don't know the term in english) thing.