Unknown Medal

A Brother on Facebook passed this photo along. He says a fellow Mason found this among his great-grandfather's possessions, and that no one can seem to identify it.

If you blow the photo up, you can make out a square and compasses with a "G", so it is Masonic. It seems to be a watch fob, and I'm sure there were dozens if not hundreds of similar ones made by jewelers around the country. Does anybody have any idea what particular organization or lodge this medal may come from?  (Click the photo to enlarge it.)