When heavy rains sweep across Zambia’s hills and savannahs, some rivers suddenly shift from their usual brown or green to a bright, unexpected turquoise. For a few hours — sometimes an entire day — the water glows like liquid gemstone. The transformation looks magical, but the explanation lies in the minerals carried by the storm.
Zambia’s landscape is rich in copper, malachite, and other mineral deposits, especially in regions like the Copperbelt and areas near Solwezi. During intense rainfall, stormwater rushes through these rocks and soils, dissolving tiny mineral particles. As this mineral-rich runoff flows into nearby rivers, it changes how the water absorbs and reflects sunlight.
Copper-based minerals are the biggest contributors. When finely ground by erosion and carried into rivers, they scatter light in the blue–green spectrum. Sunlight hitting the water bounces back in shades of turquoise, creating the sudden colour shift.
The effect is strongest where the river is shallow, the sun is bright after the storm, and the flow is fast enough to mix the minerals thoroughly. As the stormwater settles and the particles sink or get carried downstream, the river returns to its normal colour — the turquoise window closes as quickly as it opened.
For people living along these rivers, the colour change is a seasonal reminder of Zambia’s mineral-rich earth — a natural paintbrush colouring the water after each storm’s sweep across the land.