A giant diamond originating from the largest rough in Angolan history will go under the hammer at Christie’s in Geneva in November.

  The emerald-cut, 163.41-carat stone will be the largest D-color, flawless diamond to appear at auction, Christie’s said in a statement Thursday. De Grisogono, a Swiss jeweler, cut and polished the stone from the 404.20-carat “4 de Fevereiro,” or February 4, alluvial rough diamond that Lucapa Diamond Company recovered from its Lulo mine in Angola in February 2016. Lucapa sold the rough for $16 million later that month.

  De Grisogono, which bought the rights to the rough stone, said teams of specialists analyzed it in Antwerp and cut it in New York. An 80-year-old master cleaver made the first cut on June 29 last year. Some 11 months later, the company was ready to send the polished stone to the Gemological Institute of America for grading.

In February 2017, De Grisogono founder Fawaz Gruosi and his team created 50 possible designs for the stone, and agreed on an asymmetrical necklace with the diamond as the centerpiece. The necklace — which the company has called “The Art of De Grisogono” — features a further 18 emerald-cut diamonds and two rows of pear-shaped emeralds.

   “Over our 251-year history, Christie’s has had the privilege of handling the world’s rarest and most historic diamonds,” said Rahul Kadakia, Christie’s international head of jewels. “The sensational 163.41-carat perfect diamond suspended from an elegant emerald and diamond necklace propels De Grisogono into a class of their own.”

  The auction will take place at Geneva’s Four Seasons Hotel des Bergues on November 14. The diamond will also appear on tour in Hong Kong, London, Dubai and New York.