LONDON.- Yesterday Sotheby’s unveiled a diamond unlike any offered before: an extraordinary 100-carat perfect diamond in a classic Emerald-cut. The remarkable 100.20-carat, D color, Internally Flawless, Type IIa stone will highlight Sotheby’s Magnificent Jewels auction in New York on 21 April 2015, when it is estimated to sell for US$19-25 million.

At this impressive scale, diamonds of this exceptional quality – D color and Internally Flawless clarity – are incredibly rare, and are considered ‘perfect’. The present example joins an elite group of just five comparable-quality diamonds over 100 carats that have ever been sold at auction worldwide.

What distinguishes the present example within this rarefied league is its beautiful shape: it is the largest perfect diamond with a classic Emerald-cut ever to be offered at auction. This modern shape gives the stone an unforgettable presence, whether it is worn as a jewel or admired on its own.

The original rough – weighing over 200 carats – was mined by De Beers in southern Africa. The current owner spent over one year studying, cutting and polishing the rough diamond to deliver the spectacular stone. The diamond will be exhibited in Dubai, Los Angeles, Hong Kong, London and Doha, before returning to New York for exhibition beginning 17 April.

Gary Schuler, Head of Sotheby’s Jewelry Department in New York, commented: “This 100.20 carat diamond is 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. It is the first true emerald-cut diamond over 100 carats to be offered at auction – the most classic of cuts, quietly elegant and very contemporary.”

Lisa Hubbard, Chairman of North & South America for Sotheby’s International Jewelry Division, said: “The rarest object of natural beauty on the market right now, this 100-carat diamond could be considered the ultimate acquisition. Simply put, it has everything you could ever want from a diamond: the classic shape begs to be worn, while the quality puts it in an asset class of its own. The stone gives you so many options – admire it un-mounted, wear it as a simple but stunning pendant, or mount in a designed jewel.”

Since 1990, when Sotheby’s sold the first 100-carat perfect diamond at auction, until the most recent example in 2013, the price per carat for these stones has increased from $125,000 to $260,000. The present stone’s low estimate of $19 million represents a valuation of $190,000 per carat.