Namibia's diamonds lie along its southern coast and under the Atlantic Ocean, in deposits made by rivers and waves over millions of years. The country has no major kimberlite mine. Instead, it mines beach gravels, old river terraces and the seabed, and nearly all the diamonds it recovers are of gem quality. That high gem proportion gives Namibian rough some of the highest average values per carat in the world.
How the coastal deposits formed
The diamonds originally came from kimberlite pipes far inland in southern Africa. Over tens of millions of years the Orange River and its ancestors eroded those pipes and carried the diamonds west to the Atlantic coast. Ocean currents running north then spread them along the shore, where waves sorted them into gravel beds on beaches and on the shallow seabed.
The long journey acted as a filter. Flawed or fractured diamonds broke apart during transport, while tougher, cleaner crystals survived. That is why most stones on the Namibian coast are gem quality. The page on diamond geology explains how alluvial and marine deposits form from eroded pipes, and the neighboring deposits south of the river are covered under diamond mines of South Africa.
Kolmanskop and the 1908 discovery
Namibia was the German colony of South West Africa when diamonds were found there. In 1908 a railway worker named Zacharias Lewala picked up a diamond near Kolmanskop, close to the port of Lüderitz, and showed it to his supervisor, August Stauch. The find set off a rush into the desert. Prospectors in some places reportedly collected diamonds by hand from the sand surface.
The colonial government responded by declaring a large stretch of the southern coast a restricted area in 1908, closed to the public. The town of Kolmanskop grew fast, with a hospital, a ballroom, a bowling alley and comfortable houses supplied with water brought in by rail. When richer deposits were found further south, the town declined, and it was abandoned by the 1950s. Today its sand-filled houses are a well-known tourist site.
The Sperrgebiet
The restricted zone became known as the Sperrgebiet, German for "forbidden area." It covers a long strip of desert running north from the Orange River along the coast. Access was tightly controlled for most of the 20th century to prevent theft and illegal mining, and the region stayed largely untouched outside the mining areas. Part of the Sperrgebiet was later declared a national park, protected for its desert plants and wildlife.
After the First World War, South Africa took control of the territory. In 1920 Ernest Oppenheimer's Consolidated Diamond Mines of South West Africa took over the coastal diamond fields. The company later became part of the De Beers group, and Oranjemund, a company town near the river mouth, became the center of operations.
Orange River and beach mining
The richest onshore deposits lay along the coast north of the Orange River mouth near Oranjemund. Mining there used enormous earthmoving fleets. Crews removed overburden, sometimes many meters of sand, to reach the diamond-bearing gravel on bedrock. In places they built sea walls of sand to push the ocean back and expose seabed gravels behind them, then swept the bedrock clean, because diamonds tend to lodge in cracks and gullies.
Gravel was processed with dense media separation and X-ray recovery, steps described on the page about how diamonds are mined. Inland, older river terraces along the Orange River have also been worked by smaller companies.
Marine diamond mining
As onshore deposits were depleted, mining moved offshore. Small-scale divers and contractors began working shallow waters in the 1960s, and a Texan named Sam Collins pioneered early offshore dredging in the same decade.
Large-scale marine mining developed later. Under the partnership described below, specialized ships have worked the seabed in water roughly 90 to 140 m deep. Two methods have been used:
- Drill ships lower a large drill bit to the seabed and suck up gravel through a pipe.
- Crawler ships lower a tracked vehicle that moves across the seabed, pumping gravel up to the vessel.
The gravel is processed on board, and the diamond concentrate is sealed and flown ashore for final sorting. Over time marine mining became the source of most of Namibia's diamond output. Offshore mining raises questions about effects on seabed life, and the operators carry out environmental monitoring.
Namdeb and Debmarine Namibia
After Namibia's independence in 1990, the government and De Beers formed Namdeb in 1994, a 50-50 partnership that took over the onshore and nearshore operations. Marine mining is run by Debmarine Namibia, also owned equally by the government and De Beers. The government set up Namib Desert Diamonds (Namdia) to sell part of the output independently, and Namibia has supported a local cutting and polishing industry. These changes mirror the partnership model in neighboring Botswana.
Namibian diamonds on the market
Namibian rough is known for its high gem proportion and good average size, which gives it a strong reputation among buyers. Most Namibian stones move through the diamond pipeline to cutting centers. For comparisons with other producing countries, see diamond mines of the world.
Frequently asked questions
Why are Namibian diamonds high quality?
Rivers and waves carried them hundreds of kilometers from their source pipes. Flawed stones broke up on the way, so mostly clean, tough crystals reached the coast.
What is the Sperrgebiet?
It is a restricted diamond zone along Namibia's southern coast, declared in 1908. Its name means "forbidden area" in German, and part of it is now a national park.
How are diamonds mined from the sea in Namibia?
Specialized ships lower drills or tracked crawlers to the seabed, pump up diamond-bearing gravel and process it on board.
What is Kolmanskop?
Kolmanskop is a former diamond town near Lüderitz, founded after the 1908 discovery. It was abandoned by the 1950s and is now a ghost town visited by tourists.