What is a blue colored silkie technically?

[nlsf]

I've been looking into getting a couple silkie chicks, but the colors have confused me very much. Some people say they have blue silkies and some say they have gray. Is there a difference? Does anyone have pictures that might help explain this? Thanks in advance!

 

[CascadiaRiver]

I've never understood the "grey thing" in silkies honestly but I am almost certain blue is a dilute of black