Whether you take offense would depend on your interpretation and expectations, in this case from her behavior. Even though you've decided to keep the stones in the family, once you decided to give the ring away, you kind of gave that choice away too. Once you give her the ring, she can always do anything to it or with it. At least she was making her intentions known early on.
Her intention may have not been to humiliate you even though you felt that way. It seems that she was just being honest about what she wants.