Here is the original stopper for a James J Murray "Bison" milk glass cologne bottle or  "Buffalo" bottle/ vanity set decanter.  The stopper is approx. 4 1/2" in length and 2 1/4" in width.  The diameter of the widest portion of the plug end is 15/16th of an inch and its circumference is 2 7/8".   This could serve as a stopper for milk glass, blue milk glass and other opaque cologne/other decanters that have a top opening diameter of about 7/8".

There are no chips or cracks.  There are small smoothed flake areas on the very bottom of the stopper as seen in the final image.