The Lesedi La Rona: the largest gem-quality diamond discovered in over a century

The geology: why Karowe produces giants

The Karowe mine, operated by Botswana-based Lucara Diamond Corp under a mining license from the Government of Botswana, sits on a kimberlite pipe in the Orapa kimberlite field in the Letlhakane district of central Botswana. The AK6 kimberlite at Karowe is unusual in the diamond mining world: it disproportionately produces large, high-quality Type IIa diamonds, chemically pure diamonds with no nitrogen impurities that tend toward exceptional transparency and colourlessness. In the years surrounding the Lesedi La Rona's discovery, Karowe also produced several other diamonds above 300 carats and dozens above 100 carats. This is not coincidence; it reflects specific geological conditions in this pipe that favour the formation and preservation of large, clean crystal growth (Lucara Diamond Corp; GIA geological references).

The Lesedi La Rona was Type IIa quality, the same chemical profile as many of the world's most famous historical diamonds including those from the Golconda mines of India. Type IIa diamonds are the most chemically pure, the most transparent, and typically the most colourless. GIA's examination of the Lesedi La Rona confirmed its exceptional quality and noted it as one of the most significant diamond discoveries in modern history (GIA; Lucara Diamond Corp press releases).

The Sotheby's auction: June 2016

Lucara Diamond Corp announced in early 2016 that the Lesedi La Rona would be sold at a special auction at Sotheby's London in June 2016. The pre-auction estimate was USD 70 million. The stone attracted extraordinary global attention; dealers, collectors, and cutters from around the world came to view it during the preview. The logistics of selling the world's most significant rough diamond were unusual: a rough diamond at this scale is not a commodity. It requires years of planning, millions of dollars in cutting investment, and specialised expertise to yield polished diamonds worth more than the rough. The pool of buyers capable of purchasing and processing a 1,109-carat rough diamond is tiny, perhaps a dozen entities globally.

The auction result shocked the diamond world: the Lesedi La Rona did not sell. The highest bid, approximately USD 61 million, failed to meet the reserve. The stone was bought in. The failure reflected the genuine commercial challenge of the asset: at USD 70 million for rough material that required an unknown further investment to yield a return, the risk-adjusted economics did not work for the bidders who showed up (Sotheby's; Lucara Diamond Corp; industry analysts).

The Graff purchase: September 2017

In September 2017, Lucara Diamond Corp announced it had sold the Lesedi La Rona to Graff Diamonds for USD 53 million. Laurence Graff, whose company has a 50-year history of purchasing extraordinary rough and transforming it through Graff's own cutting facilities, was in many ways the logical buyer. Graff has the specialised expertise, the financial resources, and, crucially, the direct-to-consumer retail operation to sell the resulting polished stones without intermediary margins. The USD 53 million price was lower than the Sotheby's estimate but reflected the genuine risk inherent in rough diamond purchasing at this scale (Lucara Diamond Corp; Graff Diamonds).

The cutting: what it yielded

Graff spent approximately three years planning and executing the cutting of the Lesedi La Rona. The planning process for a diamond of this size is itself an extraordinary undertaking: mapping the internal inclusions and crystal structure, determining the optimal cutting strategy to yield maximum value from the rough, and designing the specific faceting for each resulting stone. The cutting team used 3D mapping technology to model the rough before a single cut was made.

The largest polished diamond yielded from the Lesedi La Rona was a 302.37-carat emerald cut, the largest polished diamond cut from the Lesedi La Rona and named the Graff Lesedi La Rona. In 2020, Graff sold the Graff Lesedi La Rona to an unnamed private buyer for USD 40 million, establishing a record price for a white diamond. The remaining rough yielded 66 additional polished diamonds ranging from under 1 carat to over 26 carats. The total polished yield from the Lesedi La Rona represented a remarkable cutting achievement and a financial outcome that justified the original purchase price (Graff Diamonds; Christie's market commentary).

Significance and legacy

The Lesedi La Rona demonstrated several things simultaneously: that established mines can still produce extraordinary diamonds a century after the great alluvial and kimberlite discoveries; that the commercial infrastructure for trading rough diamonds at exceptional scale is genuinely constrained; and that the transformation of exceptional rough into polished diamonds of maximum value requires specialised expertise that only a handful of organisations in the world possess. Its journey from mine to final sale, five years, three organisations, two continents, is a compressed history of the modern diamond trade (Lucara Diamond Corp; Sotheby's; Graff Diamonds; GIA).