What Color is this?

FlorianGH

I can't really identify this color.

Vosblokjes

Hard to see without reference, lighting can also mess up things.
My best guess is Dark Stone Gray (or maybe (old) Dark Grey)

CG - Belgium

It looks like Dark Stone Grey. Pick a set with the same colour of brick and look for the inventory of it. Might help you on the way. That's how I learned some of the colours at first. Didn't make much mistakes so far.