Wow Mariposa, your grandmother's ring is so beautiful! I've never seen a ring like it and the mine cuts make it very interesting. Gorgeous profile too. Not bad for a placeholder!!!
ETA-I agree about leaving the chipped stone as-is, unless the stone is so damaged it is in danger of falling out.
That is such a beautiful ring, but then again I am biased as it looks almost exactly like my wedding ring (I don''t have an e-ring). My ring was bought as an antique but I have no idea how old it is, this gives me some idea I suppose. Thanks so much for posting.