Flawless diamond sells for $15.7M, makes auction history

On Monday evening an exceptionally rare 102.39-carat diamond made auction history as the first gem of its quality to be sold without a reserve.

With a live auction taking in online and phone bids, the opening price was $0.13, but eventually climbed to the winning bid of $15.7 million.

Cut from a rough diamond discovered in 2018 in Ontario, Canada, the oval stone received the highest bid placed for a jewel online, nearly $11 million, but eventually went to a telephone bidder in Japan, a private collector who quickly called the stone “Maiko Star” after one of his daughters. This same collector purchased a diamond from Sotheby’s last year, naming it “Manami Star” after his eldest daughter.

While Sotheby’s had declined to provide a pre-sale estimate, the auction house had been expected to attract huge bids for the item after it achieved top rankings in each of the “four Cs” by which a diamond is judged: cut, color, clarity and carat weight.

The stone had also been classified as “D color,” the highest grading for a white diamond. It is considered to be internally and externally “flawless,” placing it among the world’s most chemically pure, transparent and symmetrical diamonds, and it belongs to a rare subgroup of diamonds that contain little to no nitrogen.

Only seven D color flawless (or internally flawless) diamonds weighing more than 100 carats had ever appeared at auction before Monday’s sale, according to Sotheby’s. Of these, the most expensive remains a rectangular 163.41-carat diamond, which sold for $33.7 million at Christie’s in Geneva, while the record sum for an oval variety still stands at $30.8 million in 2013.

Unusually, the rare oval diamond at Monday’s sale was offered without a reserve, meaning that it would have been sold regardless of the size of the highest bid.

Prior to the sale, the item was displayed at appointment-only previews in Beijing, Shanghai, New York and Taipei. Bidding had been open online for almost three weeks before the sale was concluded at Monday’s live auction.

Photos: Diamonds up for auction

Take a look at photos of diamonds up for auction over the years.