My engagement ring has a 3.4 carat old mine cut diamond on a beautiful antique-style platinum setting. The stone is over 100 yrs old and is sentimentally invaluable as well as very valuable $. I have been wearing it for less than two years and in that time, the stone has come loose three times – it has not fallen out of the setting, but has come loose and moves around in the prongs. I have talked to the jeweler about this issue and she says that it is happening because the stone is so large and has a few tiny chips on it, so it is wearing down the platinum. i am beginning to doubt the craftsmanship on the setting of the ring, along with the ethics of the jeweler. any thoughts....