Selena Gomez may have shown off her engagement manicure at the Chanel Academy Women's Luncheon on December 11, but hours later she saved the engagement ring itself for a dazzling Instagram debut. Revealing her engagement to producer Benny Blanco, she shared a close-up shot of her new jewelry against a pale pink background. The diamonds are objectively huge, so there was no need to enlarge them.

The Emilia Perez star shared the news with family and friends, dressed in her favorite Banana Republic jeans and fur coat. Gomez is wearing a marquise-cut diamond, which Anne Grimmett, vice president of merchandising for Jared Jewelers, estimates represents only 5 percent of all diamonds sold today. 18th century France, when King Louis XV gave his lover, the Marquise de Pompadour, who requested a diamond cut in the shape of her lover's lips. Because of their rarity, marquise diamonds have been the top choice for celebrity engagement rings for centuries, from Jennifer Lopez and Ben Affleck's first marriage to David Beckham and Posh Spice. More importantly, the cut is “rare” enough to be shouted out in Gomez's 2015 song “Good for You.”

Selena Gomez calls herself a “marquise diamond that would make Tiffany jealous” in the song. She also calls herself a “14-carat” quality in the opening verse. Benny Blanco did not produce the song, but must have listened to it several times before buying the ring about 10 years later.

Jewelers for Gomez's ring have yet to come forward to confirm its value. Diamond experts have gotten enough looks to appraise it from afar. Jared Grimmett said in a press release, “Considering the large center of the eternity setting, at about 6 carats, the value would be about $225,000.” Meanwhile, gemologist Laura Taylor of Lorelle Diamonds put the value even higher, at $1 million, in an interview with the Daily Mail.

Marquise diamonds are not as common as oval or cushion cuts, but Selena Gomez's engagement ring is sure to spark a fresh trend among brides-to-be. They are regal but not too assertive, and fit any bridal aesthetic. Gillian Sassone of Marrow Fine Jewelry says, “Marquise diamonds look like larger stones, with elegant, pointed tips traditionally associated with royalty. Marquise diamonds look stunning in both prong-set and bezel-set settings.

Now that we're all familiar with Selena Gomez's engagement ring, let's fantasize about her wedding. Do you have any guesses as to the style of dress she will wear?