The cushion shaped diamond of perfect D colour from the ancient mines, where the famous Koh-i-Noor and Blue Hope diamond originated, fetched a record price at an auction late last night, Guardian reported quoting an announcement by the Christie's.
"It is a world record for a Golconda diamond and a world record price per carat for a colourless diamond," Francois Curiel, director of the international jewellery department at Christie's, told reporters.
"It is comparable in its noble lineage and superb quality to the legendary Koh-i-noor," he said, adding that it was sold to an anonymous bidder and may apparently be on its way to a museum.
The rare colourless diamond, weighing 76-carat was named after Austria's Archduke Joseph August, a prince of the Hungarian line of the Hapsburgs, who reportedly deposited it in a bank vault in 1933.
"Three years later it was sold to a European banker, and kept in France, locked away in a safe deposit box, where fortunately it remained undiscovered during the second world war," the auction house said.
It surfaced at auction in 1961 and again at Christie's in November 1993, netting £4m at the time. The stone was subsequently "slightly recut".
The diamond was sold by American jeweller Black, Starr & Frost and was a star lot at Christie's semi-annual jewellery sale in the Swiss city of Geneva.
Historical diamonds originating in the Golconda mines, virtually exhausted by the 18th century. They included the Koh-i-noor, now in the British crown jewels, and the blue Hope Diamond, part of the Smithsonian Institute in Washington DC, Christie's said.