Jessica Simpson Engagement Ring PhotoJust a week after Jessica Simpson's ex-husband proposed to longtime love Vanessa Minnillo with a giant Asscher-cut diamond, Simpson flashed her own whopper: a ruby-and-diamond Neil Lane engagement ring.

Simpson wore red nail polish to coordinate with her statement bauble from NFL player Eric Johnson when she stepped out Nov. 14 at Dillard's department store in Kansas City, Kan., to promote her clothing line. Fans told People the "Project Runway" finale judge was glowing and happy. Natch.

Simpson's second engagement ring features an approximately 4-carat, oval-shaped ruby stone flanked by two diamonds from Lane, a Los Angeles jeweler known for his celebrity bridal clientele.

Jewelry expert Gus Davis of New York City-based Camilla Dietz Bergeron tells StyleList the ring is undoubtedly a rare vintage piece, circa 1900, with a retail value of at least $100,000. "It's a classy ring for a classy lady," he says.

The retro ring is flanked by "old European cut" diamonds of approximately 2 carats each, says Davis. "One would assume for a ring of this period that the ring is of Myanmar [Burma] region mounted in yellow gold."

Here's hoping the couple's love is as rare as its symbol: "This is a ring that will never go out of style and resonates timeless elegance," says Davis, whose firm specializes in luxury estate pieces. "Original rings from this period are very hard to find, especially a ruby of this size and quality."