A Car badge for Tanganyika with the Williamson logo. 
From Nairobi it was a short flight in the John Thoburn Williamson
John Thoburn Williamson was born in Montfort, Quebec
on the 10th February 1907 and went to McGill University Montreal where he gained a B. A.
degree in 1928, an M. Sc. in 1930, & a PhD in 1933. a rugged Canadian geologist who, after he
was sacked from the African Diamond Development Corporation in 1936 began prospecting on his own for diamonds in what
is now Tanzania.
Just as the sun rose on the 6th March 1940, after nearly five years prospecting under the remorseless tropical sun in the bush his black African helper handed him a pebble. Williamson held it up to the sun and immediately saw that it was a green diamond. He scraped the mud away beneath his boots to light a fire as it had rained heavily during the night. The solid rock under was Kimberlitic, he had found his volcanic pipe at last. Now he had to survey the the pipe without raising any suspicion, he spent months digging trenches and then backfilling them on his covert surveying mission. Over the years he had run out of backers except for one Asian Lawyer, Mr I C Chopra who was the only person he could trust, before finally staking his claim in Dar-es-Alaam. Williamson kept a 90% stake with Chopra having the remaining 10%. He had found the largest diamond deposit ever, the oval-shaped volcanic pipe which was filled with diamondiferous ore covered some 361 acres on the surface; more than four times larger than any of the diamond pipes found in South Africa. He named the site after the local Tribal Chief Mwadui.
A De Beers team of prospectors had surveyed the territory a decade earlier without reporting any trace of diamonds. Now De Beers had to prevent Williamson from flooding the market with these diamonds. When the extent of the diamond strike became clear in 1945, Ernest Oppenheimer offered Williamson 2 million pounds 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 Asian 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 his 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 made 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 1st photo above is JTW celebrating his 43rd birthday on the 10th February 1950 while he was rich beyond dreams with diamonds but completely cash strapped.
The lower photo's are JTW standing by the Baobab tree where he found his first diamond at Mwadui, and checking his diamonds in his office.
Bwana Williamson died on the 7th January 1958 just a few days short of his 51st birthday of throat cancer. He was buried in the cemetery where it all began at his beloved Mwadui.His siblings inherited the mine and immediately started negotiating a sale.
Williamson Diamonds Limited was bought 50/50 by De Beers and the Tanganyika Government on the 13th August 1958 for just £4 million GBP.
