This black glass button is backmarked, "PAT'D DEC. 23, 1880" and has a brass plate and loop shank. It is slightly concave and has a molded scene of a castle and bridge. It measures 5/8" NBS Small. It's in good condition, other than 1/16" shallow chip at the bottom near the 5 o'clock area at the edge. Not detracting to the beauty of the button, in my opinion. The scanner makes it look worse than it is. $8