The Lesedi La Rona - Setswana for Our Light - is a 1,109-carat gem-quality rough diamond recovered on 16 November 2015 at the Karowe mine in Botswana, operated by the Canadian-listed Lucara Diamond Corp. At the time of recovery it was the largest gem diamond found in over a century and the second-largest gem diamond ever recovered, exceeded only by the 3,106-carat Cullinan of 1905. The stone is Type IIa, chemically pure with no measurable nitrogen, and was assessed as exceptional D-colour material with high clarity potential.

Recovery

The Karowe mine, in central Botswana, has produced an unusual concentration of large stones since opening in 2012; the Lucara operation deploys an XRT (X-ray transmission) sorting circuit specifically designed to recognise and divert large diamonds before they can be damaged by the conventional crushing and recovery process. The Lesedi La Rona was extracted intact from the AK6 kimberlite pipe and was, on recovery, the largest diamond produced by any operation in over 100 years; subsequent finds at Karowe include the 1,758-carat Sewelo (2019) and several other stones over 500 carats.

Sale and cutting

Lucara offered the Lesedi La Rona at a Sotheby's London single-lot auction on 29 June 2016, with a pre-sale estimate above U.S. $70 million; the stone failed to sell at auction, attracting a high bid of approximately $61 million which was below the reserve. In September 2017, Lucara announced a private sale to Graff Diamonds for $53 million. Graff committed to cut the rough into a series of polished diamonds and disclosed the project publicly over subsequent years.

From the rough, Graff produced a 302.37-carat emerald-cut polished diamond named the Graff Lesedi La Rona, certified by GIA as D-colour and high-clarity; this is the largest emerald-cut diamond in existence and the largest highest-colour, highest-clarity diamond ever certified by GIA. Sixty-six additional satellite diamonds were polished from the remainder of the rough, ranging from approximately 0.55 to 26 carats; each was laser-inscribed with a unique number tied to the parent rough.

Significance

The Lesedi La Rona is a reference recovery in modern diamond mining: it demonstrated the commercial viability of XRT large-stone sorting, accelerated investor and industry attention on Botswana as a producer of historic large diamonds, and contributed to the cluster of recoveries at Karowe that has made the mine the most productive source of plus-100-carat stones in the modern era. The Lesedi La Rona's failure to sell at auction in 2016 was also instructive: it showed the limits of the single-lot rough-diamond auction format and the importance of negotiated private sale for stones of singular character.

Status

The 302.37-carat polished centrepiece and the satellite diamonds remain in private collections following sale by Graff. The Graff Lesedi La Rona has been displayed publicly only intermittently and is not currently exhibited. The Karowe mine continues in operation, and further large recoveries from Botswana have entered the market in subsequent years - though none has yet exceeded the Lesedi La Rona except the 1,758-carat Sewelo, also from Karowe and sold to Louis Vuitton in 2020.