It has to be smaller to be all copper. Smaller than the dime. And cost less than one cent to mint. A half cent of copper would be one centimeter or 3/8ths of an inch in diameter and one millimeter thick.
would be one centimeter or 3/8ths of an inch
LOL! Well I gotta admit that's close enough for a quick comparison.
So don't mind me... I just suffered an engineer's primal urge to point out that 3/8" is .0187" short of a cm.
But I don't think they teach that in school anymore... everything's done with pushbuttons...