A flawless 100.2 carat emerald cut diamond achieved $22.1m in Sotheby's April 21 Magnificent Jewels auction in New York.

The stone is described as internally flawless, meaning it displays no imperfections, and is the largest of its grade ever to cross the block.

The diamond is the largest of its grade ever to come to auction

Lisa Hubbard, chairman of Sotheby's international jewellery division, commented: "This diamond is exceptional in every sense of the word, and we were thrilled to see it achieve such a strong result.

"The stone captivated people around the world throughout our extensive travels this spring…

"Including today's result, only six perfect diamonds weighing over 100 carats have sold at auction in the last 25 years - a testament to the incredible rarity of these stones."

The sale realised a total of $65m, a record for a jewellery auction held by Sotheby's at its New York headquarters. Other top selling lots included a 22.3 carat diamond and platinum ring that made $3.3m.

Gary Schuler, head of Sotheby's New York jewellery department, said: "It was encouraging to see the impact of private collectors throughout the day, including at the highest end of our sale: eight of our top ten pieces were purchased by private individuals.

"Our strong results spanned each of the categories that have driven the auction market in recent seasons: top-quality diamonds and gemstones, signed and historic jewels, and pieces with notable provenance."

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