thumb|Williamson, 1957
John Thoburn Williamson (1907–1958) was a Canadian geologist famous for establishing the Williamson diamond mine in present-day Tanzania; he was the only man in the 20th century to create his own diamond mine.
Williamson mine
After completing his studies, Williamson travelled to South Africa with one of his professors, where he eventually took a job with Loangwa Concessions, a De Beers subsidiary in what was then Northern Rhodesia (now Zambia). He then moved on to work at the Mabuki diamond mine, which he purchased from the owners in 1936 when they had decided to shut the mine down. Williamson struggled to support himself with the operations of the Mabuki mine, while using it as a base for diamond prospecting in the region. Additional funding came from local lawyer Iqbal Chopra, who partnered with him on his future discovery. The mine, famous for being the first significant diamond mine outside of South Africa, continues to operate today, and the total production from 1941 to 2008 has been estimated at 20 million carats (4,000 kg) of diamonds.
The mine produced many fine gems including the Williamson pink diamond, a pink rough diamond presented to Princess Elizabeth and Prince Philip on the occasion of their wedding in 1947. Cut by Cartier to a gem, it became the centerpiece of the Williamson Diamond Cartier brooch made for the Queen in 1952. In 2011 Williamson was inducted into the Canadian Mining Hall of Fame.