Graff Lesedi La Rona

LONDON — Continuing its mission to source exceptional stones, Graff said Tuesday that it has acquired the world’s largest diamond following a year-long negotiation.

The diamond, named Lesedi La Rona, weighs 1,109 carats and is the size of a tennis ball. It was acquired by Laurence Graff, the company’s chairman, for $53 million from the chairman of Canadian mining company Lucara Diamond Corp.

It originally failed to sell at a Sotheby’s sale held in June 2016.

Graff said his team of master craftsmen will work “night and day to ensure that we do justice to this remarkable gift. The stone will tell us its story, it will dictate how it wants to be cut, and we will take the utmost care to respect its exceptional properties. This is a momentous day in my career.”

The diamond is the largest rough diamond discovered in the last 100 years. It was found in Botswana and, according to the Gemological Institute of America, it stands out for its quality and transparency.

Tobias Kormind, managing director of the online retailer of diamond jewelry, said that the sale marks an important moment for Britain’s heritage in diamonds.

“The only larger diamond previously unearthed was the 3,106-carat Cullinan Diamond, discovered in South Africa in 1905, and it was cut into smaller stones, the largest of which is the 503-carat Star of Africa, which sits in the Queen’s Sceptre within the Crown Jewels. It’s unlikely the Lesedi La Rona will yield a larger diamond than that, because the priority for Graff will always be quality, not size, but the stone could yield two pear-shaped diamonds of over 200 carats each,” said Kormind.

“It is likely to be welcomed by Graff’s core clients, who adore enormously dramatic jewels of historic proportions.”

Earlier this year, the jeweler also acquired a 373.72-carat rough diamond that was originally extracted from the Lesedi La Rona rock, as well as the largest heart-shaped diamond in the world, which weighs 118.78 carats, or 23.5 grams.