The largest coloured diamond ever graded at the Gemological Institute of America has set a new auction record, after it was sold at Christie's Magnificent Jewels auction.
The stone brought an impressive $2.1m, rising 75% above its $1.2m high estimate. It now holds the title of the most valuable reddish-orange diamond ever sold at auction as well as setting a new per-carat record price for a diamond of its type of $666,200.
Circular cut and unmounted, the diamond exhibits the two rarest hues known. How the stone got its extraordinary red and orange colouration is not yet fully understood, though it is believed to be due to nitrogen and hydrogen being present as the crystal lattice is forming.
The diamond was sold complete with a letter from the Gemological Institute of America confirming that it is the largest it has ever seen. The largest known red diamond is currently on display at the Smithsonian Institution, weighing 5.03 carats.
Attracting the top bids of the auction was a spectacular diamond ring by Graff, which was set with a rectangular-cut diamond weighing 50.01 carats. The ring was purchased for $8.4m - within its $7m-10m estimate - by Laurence Graff.
"This is the third time that I have owned this beautiful diamond and I am as thrilled today as I was the first time," noted Mr Graff after the sale.
"Diamonds of this exceptional calibre have a life and legacy that carries on beyond us all.
"This is one of the finest D-colour diamonds in the world and I am delighted to have it back again."
The auction was the last jewellery sale of the season for Christie's, so be sure to sign up to Paul Fraser Collectibles free weekly newsletter to ensure you don't miss out on the latest news on next year's offerings.