Whtiehead and Hoag Pin

I found a Whitehead and Hoag pin in my attic when I was a little girl.  It has two parts.  The pin, which looks to be made of silver and maybe ivory.  It has the letters U.D.C on it.  the metal around it is very ornate.  It also looks like that there was a ribbon that connected to the second piece which is a medallion that is also surrouned by a very ornate silver or maybe pewter.  It has a picture of a woman, with two flags.   The back of the medallion piece has the Whitehead and Hoag stamp.  Not sure if it is a treasure or not.

Fair