At Olduvai Gorge, a piece of chert may have no price per carat and no buyer in an overseas market. Yet a stone deliberately flaked by an early toolmaker is priceless to archaeology: it preserves evidence of a human decision made deep in prehistory.
In the Mererani Hills, tanzanite is measured in carats, dollars and public revenue. Mererani is the only known source of gem-quality tanzanite, a fact that gives the stone a distinctive place in Tanzania’s mineral story.
These are two ways of valuing stone. One preserves scientific memory. The other drives trade and industry. Tanzania’s challenge is not to choose between them, but to protect both.
Long before gemstones reached jewellery shops and mineral markets, early humans were already making careful choices about stone. At Olduvai, hominins used lava, quartzite and chert for tools, selecting materials according to their sharpness, durability and the purpose of the tool. Research shows that this decision-making stretches across more than 1.8 million years of occupation at the gorge.
“Prehistoric people placed high value on different rock types based on their physical and chemical properties,” says Daniel Jackson Masika, a researcher and master’s student in Palaeolithic archaeology at the University of Dar es Salaam.
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Toolmakers, he explains, sought stones with high silica content and fine, even grains because they could be struck to make sharp edges rather than breaking along unpredictable natural planes.
That history complicates the meaning of value. A gemstone may be valuable because it is rare, beautiful, fashionable or difficult to obtain. A stone tool may have no monetary price at all, yet be irreplaceable to archaeology. By one measure, a worked stone at Olduvai can be as important to understanding humanity’s past as tanzanite from Merelani is to the global gemstone trade.
The two kinds of value can coexist. Former Geological Survey of Tanzania chief executive Prof AbdulKarim Mruma has described Tanzania’s geological setting as conducive to multiple forms of mineralisation.
Whatever a mineral becomes in the market, its story begins underground, in conditions formed long before there was anyone to trade it.
More than raw exports
That underground potential is increasingly visible in Tanzania’s public accounts. Government mining revenue rose from Sh526 billion in the 2020/21 financial year to more than Sh1.071 trillion in 2024/25. The sector’s target for 2025/26 is Sh1.2 trillion.
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Minerals are no longer peripheral to the economy. They are increasingly linked to public revenue, investment, jobs and Tanzania’s place in international markets. But extraction alone captures only part of a mineral’s eventual worth.
Much of the higher value lies further along the chain: cutting, polishing, grading, jewellery-making, branding and marketing. The Ministry of Minerals defines value addition as refining, processing or transforming raw minerals into finished or semi-finished products. Its own model includes cutting tanzanite to jewellery grade.
Every stage completed in Tanzania, rather than overseas, offers a chance to build skills, businesses and higher-value exports. The goal is not simply to sell a stone. It is to make more of its value remain in the country.
Graphite shows how this logic applies beyond gemstones. The Ministry of Minerals has identified graphite as a critical mineral and has argued that local processing can turn it into higher-value material for battery production. This matters because graphite is among the minerals crucial to battery performance, longevity and energy density.
In May 2026, the Ministry expressed an ambition for Tanzania to become one of the world’s major graphite producers. Whether that target is met will depend not only on mining output, but on whether the country can capture more of the processing and manufacturing value chain.
What Tanzania keeps
There is a third form of value that no revenue table or carat price can capture: knowledge. Archaeological stones help researchers reconstruct choices made by people long ago. Mineral deposits help geologists reconstruct the Earth’s history. Gemstones reveal the uniqueness of particular landscapes.
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Tanzania’s mineral wealth is therefore both a natural archive and an economic resource. These roles need not compete. But holding them together requires deliberate choices: protecting archaeological sites as extraction expands; funding geological research alongside mining infrastructure; and building local capacity in cutting, processing and jewellery manufacturing.
The measure of mineral wealth is not only what a stone earns when it is sold. It is also the knowledge, industry, identity and lasting prosperity Tanzania builds before that stone, or its archaeological context, is lost forever.
Mariam Gichan is an archaeologist and journalist based in Dar es Salaam. She can be reached at mariamgichan@gmail.com or on +255 754 215 690. The opinions expressed here are the writer’s own and do not necessarily reflect those of The Chanzo. If you are interested in publishing in this space, please contact our editors at editor@thechanzo.com.
