World's Largest Diamond Discovered in South Africa

Context

By the turn of the twentieth century South Africa had become the dominant source of the world's diamonds, following the late-nineteenth-century finds that drew prospectors and capital to the region's kimberlite pipes. The Transvaal Colony, under British administration after the Second Boer War, encouraged new mining operations that promised both private profit and public revenue in a territory still recovering from conflict.

The Premier Mine, situated near the village of Cullinan roughly forty kilometers east of Pretoria, was one such venture. Opened in 1902 by mining entrepreneur Thomas Cullinan, it quickly yielded high-quality stones from an open-pit operation. The enterprise operated amid a competitive field that included established players such as De Beers, reflecting the close links between colonial governance, private capital, and mineral extraction that shaped southern African economies at the time.

What Happened

On the afternoon of 26 January 1905, Frederick Wells, surface manager at the Premier Mine, was conducting a standard inspection of the pit wall when he noticed an unusual reflection about 5.5 meters below the surface. Climbing down, he carefully freed a massive rough diamond embedded in the blue ground. The stone measured approximately 10.1 centimeters in length, 6.35 centimeters in width, and 5.9 centimeters in depth, and it weighed 3,106 carats.

Wells immediately secured the find and reported it to mine owner Thomas Cullinan. The near-colorless gem, with a faint blue-white tint and a small internal pocket that produced rainbow effects under certain light, was three times larger than the previous record holder, the 1893 Excelsior Diamond. Four of its surfaces were naturally smooth, suggesting it had once formed part of an even larger crystal that had fractured underground.

The discovery occurred only three years after the mine's opening. The stone was soon placed on public view at the Standard Bank in Johannesburg, where thousands of visitors came to see it before it was prepared for shipment to London.

Aftermath

In April 1905 the rough diamond was sent to London for sale through the mining company's agents, though it attracted no buyer despite widespread interest. Two years later the Transvaal government stepped in, purchasing the stone for £150,000 with the explicit intention of presenting it to King Edward VII as a token of colonial loyalty.

Prime Minister Louis Botha arranged the gift. On 9 November 1907, at Sandringham House, the diamond was formally handed over to the king by the colony's agent-general in the presence of dignitaries. Edward VII accepted it for himself and his successors, ensuring it would remain among the Crown's historic jewels.

Legacy

Joseph Asscher and his team in Amsterdam spent eight months cleaving and polishing the rough stone, producing nine major gems and numerous smaller brilliants. The two largest—Cullen I, or the Great Star of Africa, and Cullinan II, the Second Star of Africa—were set into the Sovereign's Sceptre with Cross and the Imperial State Crown respectively, where they have featured in every British coronation since 1911.

More than a century later the Cullinan remains the largest gem-quality rough diamond ever recorded. Its journey from a Transvaal mine pit to the heart of the British regalia illustrates both the economic centrality of diamond mining in early-twentieth-century southern Africa and the lasting material ties forged between colony and Crown.