Shield Pointed at Bottom, with Battlements at Top

by Diane Young
(Indiana)

this is a ring I inherited from my grandmother and she may have gotten from her mother. It is an aquamarine with diamond bag-gets on the sides. Inside of the ring it has a 10K gold mark on one side and the shield with battlements on the other. I have no idea what the mark is, but the description is the best I can make out. Is this anything significant?