Hi kirn_malinus,
I don't know if your grandfather was american-born, but if he was not and of European origin then you might want to look at student organizations in the respective country. "www.studiant.com" has a great variety of fraternity listings in Europe including, Germany, Belgium, Austria, Poland and the baltic republics that also have a rich fraternity life (there, however, each chapter has it's own coat of arms). Maybe that's where this ring/coat of arms originates.
Good luck, matthewg
http://www.kdstv-bodensee.de