Jewelry collectors will soon have several rare chances to add a beautiful blue diamond to their vaults.

Starting this fall, Sotheby’s will auction off eight blue diamonds from luxury jeweler De Beers. The group, called the De Beers Exceptional Blue Collection, was sourced from South Africa’s renowned Cullinan mine, and is impressive given that blue is the rarest color to find in a diamond. What makes these eight significant is that their brilliant hue and even color distribution make them particularly rare. What’s more, four of the eight stones were graded by the Gemological Institute of America (GIA) as “fancy vivid”—the highest grading for colored diamonds. The eight diamonds vary in shape and size, ranging from a 1.2-carat oval shape to an 11.29-carat step-cut. Altogether, they weigh more than 32 carats. The total collection is valued at over US$70 million.

“The magnificent De Beers Exceptional Blue Collection stands as a testament to De Beers’ unique ability to source the rarest diamonds in the world and the patience and foresight required to assemble a collection that transcends rarity and can only be called remarkable,” says Bruce Cleaver, CEO of the De Beers Group in a statement.

Three of the diamonds will be offered at auction before the end of 2022, while the remaining stones will go under the hammer at later dates. The De Beers Exceptional Blue 5.53, valued at US$11 million to US$15 million, will be sold during Sotheby’s Magnificent and Nobles Jewels auction in Geneva on November 9. The Exceptional Blue 3.24 (US$5 million to US$8 million) and the Exceptional Blue 2.08 (US$1.2 to US$1.5 million) will go under the hammer during the Magnificent Jewels in auction in New York on December 7.

This isn’t the first time Sotheby’s has offered the geological rarities. In fact, in April, the house sold a 15.10 carat De Beers blue diamond at auction for a gob-stopping US$57.5 million.

“The market for colored diamonds and precious gemstones has never been stronger, so we are absolutely thrilled to be offering the first diamond of this superb collection,” says Olivier Wagner, Head of Sotheby’s magnificent jewels auction in Geneva, in a statement.

Make room in your jewelry box—and call your accountant.