Newsletter #4 Now Available - March 2026
The latest Overberg Geoscientists Group (OGG) Newsletter #4 is out now!
This presentation covers the alluvial diamond deposits of the Ural Mountains, the discovery of diamondiferous kimberlites in Siberia’s Yakutia Region in 1954, and the recognition of kimberlites in Northern European Russia’s Arkhangelsk Region in 1975, with the Pomorskaya kimberlite pipe located in 1980. Russia has been the world’s largest diamond producer by volume, followed by Botswana.
Dr. Bristow’s talk is rooted in his first visit to Russia in 1990, during significant political change, including the transition from Communism. Subsequent visits led to collaborations with diamond researchers, explorers, and miners, and on-the-ground project work. Despite harsh climates and geographical challenges, Russia has established a world-class diamond mining and marketing sector.
The presentation also touches on the 2,000-year history and accomplishments of Russia in music, art, science, and technology. It includes insights into the 1990s, Russia's first multiparty elections, Boris Yeltsin’s leadership, and the political transitions that shaped modern Russia.
John completed an MSc in Geology at the University of Natal (1976) and a PhD in Geochemistry at UCT (1981) on the Karoo volcanics. He later studied volcanic deposits in the USA and built a successful career in the minerals exploration and mining industry, particularly in diamonds, starting with De Beers and moving into his own ventures.
Event Details:
Breakfast (R130 per person) at 10:00 AM, followed by the presentation (in person and via Zoom) at 11:00 AM.
To attend, contact:
Annabelle Greeff: annabelle.greeff@gmail.com / 082 443 0699
Hennie Greeff: hennie.greeff@gmail.com / 082 569 5314
Be sure to book your spot for this engaging talk!


The Mirny kimberlite diamond mine (Yakutia) as seen from space.
The Overberg Geoscientists Group is a collective of geoscience professionals and enthusiasts dedicated to exploring the Earth's physical structure, from rocks and minerals to geological processes, across the greater Overberg region. The group engages in research, field studies, educational activitie...
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