Christened the Bleu Royal, this diamond weighs an impressive 17.61 carats

Even if you’re not getting married, this something blue is well worth your time.

A massive blue diamond nicknamed Bleu Royal will be auctioned off by Christie’s this fall, during the house’s Magnificent Jewels sale in Geneva. The stone will be the largest internally flawless fancy vivid blue diamond to ever appear at auction—and it comes with the price tag to match: Estimates for the gem currently sit at US$35 million to US$50 million.

“This is a true miracle of nature,” Rahul Kadakia, Christie’s international head of jewelry, said in a statement. “Over our 257-year long history Christie’s has had the privilege of offering the world’s rarest gems at auction, and Bleu Royal continues this tradition. We are proud to offer collectors the opportunity to own a diamond fit for Royalty.”

Bleu Royal, which weighs an impressive 17.61 carats, has been cut and polished into a symmetrical pear shape and set in a ring. One of the rarest diamonds to have ever been unearthed, according to Christie’s, it’s been part of an anonymous private collection for the past 50 years.

Christie’s noted that fancy vivid blue diamonds are extremely rare, and that prices for coloured gems have risen exponentially over the past few years. The auction house has only sold three such diamonds in its past: In 2010, the 10.95-carat Bulgari Blue hammered down for US$15.8 million. That was followed in 2014 by the 13.22-carat Winston Blue, which fetched US$23.8 million. And in 2016, the 14.62-carat Oppenheimer Blue sold for an eye-popping US$57.5 million.

Potential Bleu Royal buyers will have to wait until the Magnificent Jewels auction kicks off on November 7, while admirers will be able to view the lots on offer throughout October in cities across the world, including New York and Hong Kong. The Bleu Royal will certainly be the star of the show, and if it hammers down for the expected US$50 million estimate, the gem would almost beat the combined total for Christie’s Magnificent Jewels auction in New York this summer. While that sale brought in a combined US$62 million, it seems the auction house is looking at an even bigger payday this fall.