I can probably give you a little more info bubbleprincessmom, I work for a jewelry manufacturer. Here is a little info to help you out...
First of all take a deep breath and relax. If it is a small side diamond the cost of the repair shouldn't be too terrible of a bite, and will probably be less than your deductible. Even if you have no deductible, you might not want to risk raising your rates for such a small claim. This might seem like the end of the world, but it happens.
Some settings are just made in ways that you can loose stones. We design our rings so this doesn't happen as much, but there are a lot of rings made overseas where the metal isn't there to hold the stones. I can tell you about some very poorly made jewelry I have seen, but yours probably isn't what I like to call "Cruise/Junket Jewelry".
When you have the diamond replaced, I would have them check the rest of the stones for tightness, and make sure that the channels don't need any reenforcement if it is channel set, If it is Pavee, well, loosing stones is part of the deal. Ask the jeweler to see a loupe (a fancy magnifying glass) and see just how little metal is holding those diamonds in. I never recommend Pavee on an engagement ring because you do loose stones. Platinum lasts longer, so if you have to have the pavee, I strongly urge you to make the ring in Platinum.
Sizing can also loosen the diamonds. We check all diamonds after the rings come out of our shop when we size a ring. I would think your jeweler did that as well.
Getting back to the ring quality, I have seen rings (generally ones made in Asia, Mexico, or other places with very inexpensive outsourced labor) put together with Solder. This means that they have lighter prongs and channels. I hope this is not the case with your ring, but this could make the problem worse.
Additionally, there is wear and tear. over time things just move, prongs get worn and need to be re-tipped. GIA (The Gemological Institute of America) recommends that you have you stones checked every 6 months.
OK, here is my recommendation, Sorry if I am repeating myself...
If you liked the jeweler who fixed your rings, take it to them and ask how much it will be to replace the diamond. Generally if it is a small stone, the repair and diamond are not a great cost, and should be much lower than your insurance deductible. Without seeing the ring I cannot give a better estimate. If you feel like the jeweler broke your ring, or was not ethical, I would try The Place The Ring Was Purchased from (if it isn't the same place), or you can find a new jeweler. If you are looking for a new jeweler and don't want to ask around you can look for industry accreditation (IE is the store a member of AGS- the American Gem Society) AGS stores have to have been in business for a few years and are required to have someone on staff who is trained and is certified to grade diamonds.
I hope this helps!!!!!
