Mailing jewelry? Check the ZIP Code, or you may end up with an irradiated gem, as one Maine goldsmith found out recently. Stephen and Judith Brown, owners of Brown Goldsmiths & Co. in Freeport, Maine, sent a first-class, insured box containing one white cultured pearl through the U.S. Postal Service. The pearl, which was set into a small plastic display, inside a jewelry box, packed inside the mailing box, was sent to a customer in Manassas, Va., a suburb of Washington, D.C.

“I talked with the postmaster of our local post office about the problem,” said Brown. “She did a little digging and said we should avoid mailing to the government metro area including ZIP Codes 200**-209**.” The ZIP Code for Manassas is 20110.

“Ken Scarratt of the AGTA [Gem Testing Center lab] explained to me that when a cultured pearl is subjected to an electron beam, the freshwater nucleus is what actually turns dark,” Brown says. “Close visual inspection seems to confirm this, as the outer nacre seems unaffected. The nucleus is clearly much darker.”

Brown wants to know how jewelers can eliminate the risk of permanently altering a customer’s pearls. “We are very thankful to have had this happen with a pearl that belonged to us and not, for instance, a strand that had been handed down in the family. As a jeweler, I am looking for an airtight strategy for mailing cultured pearls and gemstones safely.”