Jamie McCarthy, WireImage

Check this out, Nick Lachey! Eric Johnson put a ring on it too.

Just 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."

Johnson and Simpson, who've been dating a scant five months, confirmed their engagement to People this weekend in what's beginning to feel like a prenuptial soap opera.

Simpson wore a traditional pear-shaped diamond during her engagement to Lachey, who starred with her in the MTV series "Newlyweds." The couple split in 2005 after three years of marriage.

Minnillo was sporting a 4.5-carat diamond by Bader & Garrin when she and Lachey touched down in Mexico to celebrate their joint Nov. 9 birthdays.

Lane can add the Simpson sparkler to the list of rocks he's supplied for several recent high-profile pairings. His rings symbolized the recent engagement of "Bachelorette" star Ali Fedotowsky to Roberto Martinez, as well as the ill-fated couplings of Bachelor Jake Pavelka and Vienna Girardi and Bachelorette Jillian Harris and Ed Swiderski.

Lane also created the nuptial keepsakes of Emily Blunt, Jennifer Hudson and Nicole Richie.

Speaking of big engagement rings, check out the princess-cut stunner "Dancing With the Stars" pro Karina Smirnoff just received from fiancé Brad Penny.

And click here for Kim Kardashians diamond ring wish.

Also, read about the affordable line of bridal rings Lane has created in partnership with Kay Jewelers.