Jewelry can have significant emotional and financial value, and negotiating to keep it during divorce could be a problem if you focus on the former and forget to explore the latter. There are two major factors to address before you reach the negotiation table.
Is it marital property?
In the case of an engagement ring, the jewelry belongs to the wife because it is a gift given before the marriage, making it separate property. However, if it is the husband's family heirloom, a judge may rule that the wife must give it back. Other heirlooms, inherited jewelry and gifts are typically separate property, as well.
Jewelry that either you or your spouse purchased after the wedding, though, become marital property. You will have to determine who gets these personal items.
What is its monetary value?
No matter how much you want the matching diamond necklace and earrings, you should not decide you are willing to trade anything and everything to get it. Instead, you need to find out exactly what it is worth. This will probably not be the price you or your spouse paid for it.
When dealing with expensive items, you do not want to rely on your own research. You should consider hiring a professional appraiser to determine the jewelry's fair market value. The appraiser should be a jewelry expert. A judge is likely to lend more credibility to a value reached by using the Uniform Standards of Professional Appraisal Practice, so you want to ask the appraiser if he or she uses this method. You may also want to find someone willing to provide expert testimony in court, in case your spouse disputes the appraisal.
Provide your appraiser with pictures, a description that includes distinguishing or unique features, details about where the jewelry came from, etc. With this information, he or she will determine the fair market value by comparing your item with similar jewelry sales at various markets such as auctions, dealers, wholesalers and retailers.
Once you have the dollar amount, you can decide rationally what items of equal value you are willing to give up to your soon-to-be-former spouse in exchange for the jewelry you want.