New York Post says that on Boston.com it is a black pen, I don't see how they can get that because something there is obviously white.
What's with the paper and FNC?! It was NOT a pen.
It's definitely white or silver colored and definitely not a pen. But he may also have brought a pen with him, since many people say he appears to have had a black pen in his right hand (not his left, which he used to pull out the mysterious item).