The Eureka Diamond, as the Hopetown stone became known, sat unrecognised on the Jacobs family farm for months. A neighbour, Schalk van Niekerk, bought it from Erasmus's mother for sheep and an ox. Van Niekerk sold it to the Governor of the Cape Colony, Sir Philip Wodehouse, for £500. It weighed 21.25 carats and was eventually identified as a diamond by Dr W.G. Atherstone. The Geological Society of London initially doubted that South Africa could produce diamonds, the geological consensus at the time held that diamonds required conditions specific to India and Brazil. Within five years, that consensus was shattered by the discovery of more diamonds than the world had ever seen in one place. : Turrell, R.V. (1987), Capital and Labour on the Kimberley Diamond Fields 1871–1890, Cambridge University Press; historical documentation of the Eureka Diamond, Kimberley Mine Museum records
Key dates: African diamond discoveries

1866: Erasmus Jacobs finds the Eureka Diamond (21.25ct) near Hopetown, Orange River
1867: Geological identification confirmed; first diamond sold for £500
1869: Star of Africa (83.5ct, later renamed Star of South Africa) found at Hopetown
1871: Four major mines opened in the Kimberley district following discovery of kimberlite pipes
1888: De Beers Consolidated Mines formed, unifying the Kimberley mines under one ownership
Sources: Turrell (1987); Worger, W.H. (1987), South Africa's City of Diamonds; De Beers Group historical records

The Star of South Africa and the rush to Kimberley

The diamond rush began in earnest after the 1869 discovery of the Star of South Africa, an 83.5-carat stone found by a Griqua shepherd named Swartbooi near Hopetown. This stone was sold through a chain of transactions that eventually brought it to the 1st Earl of Dudley for £25,000, an enormous sum that confirmed to the world that South Africa was a genuine diamond source of exceptional quality. Within months of its discovery, prospectors flooded the Orange and Vaal river regions from across southern Africa and beyond (Turrell, 1987, op. cit., pp. 18–24; Roberts, B., 1976, The Diamond Magnates, Hamish Hamilton, London).

The 1871 discoveries at Kimberley, specifically the opening of four mines named Du Toits Pan, Bultfontein, Dutoitspan, and the Kimberley Mine itself (known as "The Big Hole"), transformed the character of the industry. These were not alluvial deposits washed into riverbeds but primary kimberlite pipe deposits: volcanic intrusions where diamonds had formed under the extreme pressure and temperature of the earth's mantle and been carried to the surface in ancient volcanic eruptions. The concentration of diamonds in the Kimberley kimberlite pipes was extraordinary, producing stones at densities that dwarfed anything previously known (Laubscher, H.P., 1972, geological analysis of Kimberley kimberlite; Roberts, 1976, op. cit.).

Kimberlite: the geological breakthrough

The Kimberley discoveries revolutionised geological understanding of diamond formation. Before 1871, the world's diamonds had come from alluvial deposits, secondary concentrations where diamonds had been weathered and transported from their original geological source. No one had found the primary source. The Kimberley kimberlite pipes were the primary source: volcanic rock columns of a specific composition (later named "kimberlite" after the city) that carried diamonds from the mantle to the earth's surface in ancient eruptions. This geological understanding transformed diamond exploration globally, the new question was not "where are the alluvial gravels?" but "where are the kimberlite pipes?" (historical documentation of kimberlite geological research; Geological Survey of South Africa records).

The transformation of diamond supply

Before 1870, the world's entire annual diamond production, from India and Brazil combined, was modest by any comparison with what followed. Within a decade of the Kimberley discoveries, South Africa was producing more carats of diamonds annually than India and Brazil had produced in the previous century. The implications for diamond prices were severe: from 1869 to 1880, the price of rough diamonds fell by approximately 90 percent as supply flooded the market. This price collapse drove the consolidation movement that eventually produced De Beers Consolidated Mines in 1888 (Roberts, 1976, op. cit.; Kanfer, S., 1993, The Last Empire: De Beers, Diamonds and the World, Hodder & Stoughton, London).

Primary sources

Turrell, R.V. (1987). Capital and Labour on the Kimberley Diamond Fields 1871–1890. Cambridge University Press. [Eureka Diamond discovery (1866), Star of South Africa (1869, 83.5ct), Kimberley mine openings (1871), diamond price collapse 1869–1880.]

Roberts, B. (1976). The Diamond Magnates. Hamish Hamilton, London. [Kimberley rush population influx; kimberlite pipe discoveries; consolidation movement; De Beers formation context.]

Kanfer, S. (1993). The Last Empire: De Beers, Diamonds and the World. Hodder & Stoughton, London. [90% price collapse 1869–1880; supply transformation; pre-De Beers market dynamics.]