The flawless 100 carat diamond sold for $22.1million

The auction house had valued the jewel, which weighs 100.20 carats, at $19-25 million, calling it “the largest perfect diamond with a classic Emerald cut ever to be offered at auction.”

Discovered in the De Beers mines of South Africa then cut, polished and perfected for more than a year, it was the highlight in 370 lots at a Sotheby’s jewelry auction.

The winning bidder took part by telephone but wanted to remain anonymous, Sotheby’s said.

The auction house had showcased the jewel twice in the Middle East — in Doha and Dubai — as well as Los Angeles, Hong Kong, London and New York in a bid to attract interest ahead of the sale.

Sotheby’s says only five comparable quality diamonds weighing more than 100 carats have been sold at auction, the most expensive of which fetched $30.6 million at Sotheby’s in Hong Kong in 2013.

Gary Schuler, head of Sotheby’s jewelry department in New York, called the stone “the definition of perfection.”

“The color is whiter than white, it is free of any internal imperfections, and so transparent that I can only compare it to a pool of icy water,” he said before the sale.