An ultra-rare $25 million blue diamond will hit the auction block at Sotheby’s Geneva Jewelry sale on November 16.

Leading the sale, the 8.01 carat rock, dubbed “The Sky Blue Diamond” was described by worldwide chairman of Sotheby’s international jewelry division David Bennett as a “wonderful clear celestial blue.” And with an estimate of $15 million–25 million, it has an equally hefty price tag to match. “It really is the color of a summer sky, with this beautiful brilliance and subtlety about the stone,” Bennett told Reuters.

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The Gemological Institute of America has bestowed its highest possible grading of Fancy Vivid Blue upon the stone. It is so rare that it ranks among the top one percent of blue diamonds examined by the institute. It has also been designated as a Type IIb, a classification that less than 0.5 percent of all global diamonds receive.

The 8.01 carat Sky Blue Diamond. Courtesy of Sotheby’s.

Cut in an emerald-style rectangular shape and set in a ring by Cartier which itself is studded with white diamonds, the piece is magnificent and eye catching enough to justify its astronomical asking price.

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While Sotheby’s has broken records for blue diamonds twice in the last two years, it is unlikely—barring an intense bidding war—that the record will be broken again. Last November, “The Blue Moon” of Josephine, a cushion-shaped 12.03 carat stone, was hammered down at $48.5 million, almost double the high estimate of “The Sky Blue Diamond.”

The 8.01 carat Sky Blue Diamond. Courtesy of Sotheby’s.

The previous record was set at the $218 million 2014 sale of the collection of Rachel “Bunny” Lambert Mellon, for an unset 9.75 carat blue diamond that went for $32.6 million.

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Other expected highlights from the upcoming sale include a “Fancy Intense” pink diamond ring weighing 17.07 carats, estimated at $12 million–15 million; an 18th century diamond ring formerly from the collection of the Imperial Russian Family, estimated at $3 million–5 million; and a mid-19th century diamond parure (a set of matching jewelry) formerly from the collection of her Imperial Highness Neslishah Abdel-Moneim, estimated to sell for $3 million–5 million.

The 8.01 carat Sky Blue Diamond. Courtesy of Ben A. Pruchnie/Getty Images for Sotheby’s.

New Yorkers can see the jewels at Sotheby’s 1134 York Avenue headquarters November 4–6, 2016.