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Gemstones of East Africa

Sunday October 20 2019

Minerals and Gemstones of East Africa by Bruce Cairncross.

Minerals and Gemstones of East Africa by Bruce Cairncross. PHOTO | JOHN FOX | NATION MEDIA GROUP 

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For the last few years I have been reviewing books on East Africa published by the Struik Nature series of Penguin Random House of South Africa.

These well-illustrated books help us know more about the animals, birds and trees you can see here, and they can enrich your days out.

But a book on minerals and gemstones? They can make you rich, of course, but they are not so easy to see as our animals, birds and trees!

Unless you have the kind of luck that the geologist and gemstone prospector, Campbell Bridges, had when he was working for the Central Mining and Investment Corporation.


The story is that one day he was walking in the bush of Komolo, south of Kilimanjaro in Tanzania, when he was charged by a buffalo.


To save himself he jumped down into a gully. He noticed a streak of green in a rocky outcrop.

It wasn’t the time to prise out a sample, with the buffalo still looking down at him. Soon afterwards, he was transferred to another area.

It took him seven years to find the gemstone again. It was tsavorite, the brilliant green gemstone that is as hard as, but rarer than emeralds.

Campbell Bridges set up a tsavorite mine in Tanzania, and when it was nationalised in the 1970s he moved to Kenya where, in 1980, he got a concession for a mine in the Taita-Taveta County.

He was murdered there in 2009 by a gang who were doing illegal mining on the concession.


But back to the new book … It is Minerals and Gemstones of East Africa, by Bruce Cairncross, who is Professor of Geology at the University of Johannesburg. You won’t find in his book stories like the Bridges and buffalo one.

It is very much a scholarly work, with many references to the sources Professor Cairncross has researched. As he says, ‘An exhaustive literature survey was carried out for this book’.

The professor gives a detailed description of the geology of the region, which includes an intricate map of where minerals and gemstones have been found.

He provides a comprehensive description of minerals, including their ‘gemological properties’, their history and their occurrences.

And there are many full-colour photographs of each mineral and gemstone specimen in his book. It features more than 60 of them.

The publisher says that the book is an invaluable reference for collectors, gemologists, students, those working in the minerals and gemstone industry in East Africa, and anyone with an interest in the earth sciences.


I don’t fit into any of these categories. And I found technical sections of the book hard to digest. But I have learnt about the importance of minerals and gemstones in the economies of the five countries of Burundi, Kenya, Rwanda, Tanzania and Uganda.

And I have learnt to appreciate the beauty of gemstones that I knew little about before — particularly the tanzanite and tsavorite varieties.

Actually, Professor Cairncross does indulge in a little humour sometimes. When, for example, he writes about the zoisite stone that is found in Tanzania, especially in the Merelani Hills of the Manyara Region — the exquisite blue-violet variety — he suggests that the famous Tiffany’s jewellery retailer in New York chose the name tanzanite because “zoisite” sounds too much like “suicide”.


Tsavorite, the emerald-green gemstone, is a variety of garnet. Though, as is noted above, the original discovery of tsavorite was in Tanzania, it has been named after the Tsavo National Park. It is now also found in Madagascar, Pakistan, Zimbabwe — and even in Antarctica. In Kenya, there are deposits in Turkana, close to the border with Uganda, as well as in the south-east.

If you have a look at this book — particularly at the array of superb photographs — I think, like me, you might well look more carefully at any rocky outcrop you come across.

John Fox is Managing Director of iDC