sterling for the mine. Even though this was an enormous sum of money then, and Williamson himself was penniless, he turned down the offer. After spending ten years on the plains of Africa in solitary pursuit of diamonds, he was not about to sell out. He wanted to build his own empire. With the backing of a number of Indian merchants and a task force of Italian prisoners of war, he began excavating the diamonds from the pipe. By 1946, he had some 6,000 workers living with their families at Mwadui, and over 200 armed guards protecting his budding empire. The entire encampment was surrounded by two barbwire fences and protected by primitive gun fortifications.

As the diamonds began to pour out of Mwadui, De Beers became increasingly concerned about its ability to control world prices. The corporate minutes of De Beers on June 20, 1946, reflect this growing apprehension. Sir Ernest Oppenheimer the chairman said that he was sure that a satisfactory outcome would result from negotiations with the British Colonial Office over a prospecting license for De Beers, but he said that the position would not be secure until they were able to come to terms with Williamson. He mentioned that the Tanganyika production was now one and one-half million pounds per annum. He very much doubted whether, at the moment, he had 65 percent effective control of world production. Oppenheimer pointed out that this uncontrolled production could prove embarrassing if there was an economic recession, and he recommended, according to the notes of the meeting, "that their efforts should be energetically directed towards obtaining effective control of all African production."

The diamond sights in London proved to be one effective means of reasserting control of the Mwadui diamonds. Dr. Williamson had to sell the low as well as high quality diamonds he mined to diamond cutters in order for his mine to be profitable. Most of the major cutting factories, especially for the more difficult-shaped diamonds, were clients of De Beers. When these clients came to the London sights, they were told, according to reports reaching the U.S. Department of justice, that they should not buy any of Williamson's diamonds. The threat was implicitly made that they might find their consignment drastically reduced or even abruptly ended if they bought any diamonds from Williamson. Since few of the cutting factories in Antwerp were willing to risk their sight in London by violating this rule of the game, Williamson found that he could only sell the clear, octahedron crystals that were in demand by small, independent cutters. He had to store most of the clear diamonds. This severely squeezed his cash reserves.

De Beers also applied pressure on Williamson through the British Colonial Office. When its representatives privately advised the British Exchequer of its stockpile of diamonds, De Beers quickly brought pressure on the Colonial Office to remedy the situation. Diamonds, after all, earned at that time more foreign exchange for Great Britain than almost any other export. At about this time, Colonial Secretary Arthur Creech Jones advanced the idea to nationalize the Williamson diamond mine. In an official white paper, Creech Jones suggested that the colonial government, through nationalization, might better be able to control the exploitation of a mineral resource than a private company.

For Williamson, the message was clear: Either he make his deal with De Beers or his mine might be nationalized. Finally, in August of 1947, Williamson acquiesced to these pressures, and Creech Jones announced in the House of Commons that Williamson had agreed to sell his entire output through the Diamond Trading Company in London. Williamson was now part of the arrangement.

The famous Williamson Pink (54.5 carat rough) was found on the surface in 1947 by the children of some mine workers at the Williamson Diamonds Mine, Mwadui, Tanzania. They took it to Dr John Thornburn Williamson's house. Dr Williamson gave the priceless cut Pink round [23.6 carat] to the then Princess Elizabeth as the centrepiece of a brooch for her forthcoming wedding to Prince Phillip.

It was in 1956, when developments at the mine were at a particularly exciting stage, that Dr Williamson first became ill - perhaps the result of his arduous years of search in the bush.

Despite treatment at leading clinics in Canada and Britain, and a lengthy world cruise, he died at Mwadui in 1958. Although he had amassed a great fortune, Dr Williamson had become known as the "world's loneliest bachelor".

Dr. Williamson thought not so much of making profits as creating something of permanent value to the country in which he had made his home. He was greatly greatly concerned for the welfare of those who worked for him.

At the time of his death, aged almost 51, Dr Williamson had poured back about £8,000,000 from his profits into the mine.This vast sum had gone towards providing equipment for the mining and treating departments, a power station, water system, workshops, houses, roads, schools and churches.

In August 1958, arrangements were completed whereby the Government of Tanganyika and De Beers Consolidated Mines Ltd became joint owners of the entire share capital of the company. This was on the understanding that none of the profits found their way to S. Africa.

A memorial to Dr Williamson stand over his grave in the quiet little cemetery at Mwadui - the town that he created.

Tanzania has been a significant diamond producer for several decades, with the bulk of production coming from the Williamson Diamonds Mine at Mwadui where commercial production began in 1925. Over 300 kimberlites are known in Tanzania of which, 20% are diamondiferous. Some 600 dipolar magnetic anomalies with similar geophysical characteristics to known kimberlite pipes have been recorded during recent geophysical surveys. Also of relevance are the psuedo-kimberlites or para-kimberlites along the young craters where diamonds have been discovered.