Ernest's 65-year grandson, Nicky, studied at Harrow and Oxford before spending 43 years at De Beers. He will step down as chairman after the deal goes through. Nicky's departure from De Beers comes eight months after he retired as a non-executive director of Anglo American after nearly four decades, leaving the mining company without a founding family member on its board for the first time.
The family has also sold down its stake in Anglo to 1.9 per cent over the years. It said yesterday it had no intention of selling its remaining shares in Anglo American, leaving it with a symbolic tie to the industry.
"This is a logical conclusion because Nicky can't go on running the business forever and there is not a natural successor to move into a senior management position. And even if there was, I'm not sure corporate governance rules would allow it these days," Mr Kilalea said.
"It is time for the younger generation to reinvent itself rather than sitting on a legal holding," he added.
The family said yesterday that it would invest much of the proceeds from the sale in Tana Africa Capital, a joint venture with Temasek, the Singapore state-owned private equity firm that invests mainly in consumer and agricultural businesses in Africa.
For Anglo American, the deal is also likely to be transformational. Cynthia Carroll, Anglo's chief executive, rejected suggestions that she might spin off De Beers in answer to shareholder complaints that its holding in De Beers is not fully reflected in Anglo's share price.
"This transaction is a unique opportunity for Anglo American to consolidate control of the world's leading diamond company - De Beers," she said.
Although the diamond price can see-saw, they are up 40 per cent this year and Anglo is essentially operating in a dream market for a player which now has pretty much all the cards - severe constraints on supply with ageing mines and no major discoveries for a decade.
Furthermore, demand from emerging market economies such is soaring, with half the weddings in Beijing and Shaghai involving a diamond, compared to virtually none a decade ago and five successive years of 30 per cent growth in India.
With China, India and the Gulf expected to equal the biggest present diamond consumer - the US, with a 40 per cent global share - by 2015, it is quite clear where Anglo's attentions will lie.
While De Beers may be targeting the rising financial imperial powers of the East, its beginnings were very much associated with colonial Britain.
The Oppenheimers may have ruled the roost for decades, but the company began with Cecil Rhodes, the English-born politician and entrepreneur who went on to found Rhodesia, which was renamed Zimbabwe in 1979 and the Rhodes scholarship scheme to Oxford University.
Mr Rhodes headed to South Africa at the beginning of the diamond rush that began in 1871, following the discovery of an 83.5 carat diamond on Colesburg Kopje, a hill situated by Kimberley, the city that rapidly formed around it as all manner of dealers and entrepreneurs flooded into the area.
Mr Rhodes, a vicar's son, began by renting water pumps to miners and, with the help of some cash from NM Rothschild & Sons, quickly established himself as king pin, merging his operation with that of his arch rival, Barney Barnato to form De Beers in 1888.
Mr Rhodes, who influenced the Second Boer War to protect his interests and exerted an iron grip on South Africa's diamond industry, later met his match in the form of Ernest Oppenheimer, a German Jewish immigrant, who became his arch rival through his fledgling operation, Anglo American.
Mr Rhodes died in 1902 and Mr Oppenheimer assumed control of De Beers a quarter of a century later.
Over the years, De Beers has been frequently attacked as operating an anticompetitive, secretive cartel - a system that De Beers referred to as a "producers' cooperative".
Given the Wild West environment that surrounded the early days of the diamond rush, it is not surprising that Messrs Rhodes and Oppenheimer fostered a business culture that is highly protective of its patch. And if Ms Carroll's talk of consolidating control are anything to go by, its new owners won't be any less protective.
- INDEPENDENT