False Promise - Barrons.com

In January of last year, I was offered a spectacular natural alexandrite, a rare color-changing gem that is among the most expensive on the planet. An oval of diamonds surrounded the gorgeous stone, all set on a classic Tiffany & Co. platinum ring. A Philadelphia jeweler, with whom I'd done business, had bought it several weeks earlier from a well-dressed woman selling her mother's estate. To be prudent, the jeweler made his purchase contingent on an inspection by the Gemological Institute of America and the issuance of a GIA Lab certificate stating the alexandrite to be of natural origin, not man-made.

My eyes popped at its luscious beauty. At last, an essential prize for my gem portfolio. A world-class alexandrite with a world-trusted GIA certificate. What could go wrong? Everything, as it turned out. After certifying the alexandrite as natural, the GIA ultimately reversed course, concurring with another lab's analysis that the gem was a fake; it was possibly the creation of rogue scientists. What follows is a cautionary tale for anyone buying jewelry with expensive gemstones. Even if you're shopping at big, brand-name jewelers, it's wise to do a little probing. The good ones stand ready to help you.