There is silver/metal on the surface of my crown, but I didn’t expect there to be any metal showing. Is this normal?

Q. I had an implant placed a few months ago and just had the crown fitted (2nd premolar upper). I thought it was just the cement etc but now that I\’ve brushed my teeth there\’s silver/metal on the surface of the crown – it looks like a small filling. I didn\’t think there would be any metal showing – is this normal?,