Where Do Diamonds Come From? The Journey from Mine to Antwerp

How are natural diamonds formed?

Natural diamonds form when carbon is exposed to extreme heat and pressure deep in the earth's mantle, about 140–200 km below the surface. Under those conditions, carbon atoms bond into a rigid cubic crystal lattice, which makes diamond the hardest natural material known.

Three conditions have to come together:

• Carbon: present throughout the earth, but only a tiny fraction ever reaches the depth needed to crystallise.
• Heat: temperatures of roughly 900–1,300 °C in the upper mantle.
• Pressure: around 45,000–60,000 times atmospheric pressure, caused by the weight of the rock above.

Most natural diamonds are between 1 and 3.5 billion years old. They reached the surface far more recently, during deep-source volcanic eruptions that punched narrow, carrot-shaped channels called kimberlite pipes through the crust. Those pipes are the primary deposits miners look for today. Over millions of years, erosion also washed some diamonds out of the pipes into rivers, beaches and the seabed, creating secondary (alluvial) deposits.

Which countries produce the most diamonds?

Russia is the world's largest diamond producer, followed by Botswana, Angola and Canada. Together, these four countries mined roughly three-quarters of the world's rough diamonds in 2024.

Source: Kimberley Process Certification Scheme, 2024 annual statistics. World total: 107.9 million carats.

Two changes stand out compared with older lists. Australia has dropped out of the top ten since the famous Argyle mine closed in 2020. And Russian diamonds no longer reach Europe: since 2024 the EU and the other G7 countries have banned Russian-mined diamonds, including stones polished in third countries.

Which countries produce the most valuable diamonds?

Namibia produces the most valuable diamonds in the world on average, at around US$417 per carat in 2024, almost five times the global average of US$88. Volume and value rarely go together: the DR Congo mines millions of carats, but mostly small, industrial-grade stones worth about US$11 per carat.

Source: Kimberley Process, 2024. Shown for the ten largest producers by volume.

Why are Namibian diamonds so valuable? Over millions of years, the Orange River carried diamonds from inland kimberlites to Namibia's Atlantic coast. Flawed or fractured stones broke apart on the journey, so the diamonds that survived are overwhelmingly gem quality. Today many of them are recovered from the seabed by specialist mining vessels.

The best gem-quality stones go to fine jewellery. Lower grades are used in industry, for cutting, drilling and polishing tools.

How did diamond mining begin?

Diamond mining began in India, where diamonds were collected from riverbeds as early as the 4th century BCE. For nearly two thousand years, India was the world's only known source.

• India (from c. 400 BCE): diamonds were traded along routes reaching the Middle East and later Europe. Antwerp's diamond trade dates back to the 15th century, when rough from India arrived through European ports.
• Brazil (1720s): gold prospectors in Minas Gerais found diamonds while panning rivers. Brazil led world supply for around 150 years.
• South Africa (1867): a teenager named Erasmus Jacobs picked up a shiny pebble on his family's farm near Hopetown. It became the 21-carat "Eureka" diamond.
• Kimberley (1871): diamonds were found in the rock itself, not just in rivers and soil. The resulting dig became the "Big Hole" of Kimberley, and diamond mining as an industry was born.

How are diamonds mined today?

Today, diamonds are mined in four main ways, depending on whether the deposit is a kimberlite pipe, a riverbed or the sea floor:

1. Open-pit mining: the top of a kimberlite pipe is blasted and excavated in terraced layers, sometimes hundreds of metres deep.
2. Underground mining: once a pit gets too deep, tunnels and shafts follow the pipe further down.
3. Alluvial mining: diamonds are recovered from riverbeds, gravels and old beaches.
4. Marine mining: specialist vessels recover diamond-bearing gravel from the seabed, mainly off Namibia.

Even at a productive mine, hundreds of tonnes of rock are often processed to recover a single carat. Modern plants crush the ore and use X-ray sorting machines to pick out the diamonds.

Not every mine is industrial. In parts of West and Central Africa, hundreds of thousands of people work as artisanal miners, digging and sieving gravel by hand. For many families this is a vital income, and responsible-sourcing programmes increasingly focus on improving their safety and fair pay.

What are conflict diamonds, and how do you know a diamond is ethical?

Conflict diamonds (often called blood diamonds) are rough diamonds sold by rebel groups to fund wars against legitimate governments. In the 1990s, armed groups in countries including Sierra Leone, Angola and the DR Congo seized mines, forced civilians to dig, and used diamond sales to finance years of violence.

The industry's response started in Antwerp:

• July 2000: the World Diamond Congress in Antwerp called for an international certification system for rough diamonds and set up the World Diamond Council.
• 2000–2003: governments, industry and civil society met in Kimberley, South Africa, to design the Kimberley Process Certification Scheme, which took effect in 2003.
• Today: every shipment of rough diamonds crossing a member country's border must travel in a sealed container with a government-issued Kimberley Process certificate.
• System of Warranties: after cutting, each invoice from trader to jeweller carries a written guarantee that the diamonds come from legitimate, conflict-free sources.

The Kimberley Process has sharply reduced the trade in conflict diamonds, but its definition is narrow: it covers rebel-funded conflict, not every human-rights or environmental concern. That's why careful jewellers go further. At Philippe Harold, every diamond we offer is certified and supplied through Antwerp's regulated trade, and we're always happy to talk you through the origin and documentation of a stone.

Who are the world's largest diamond mining companies?

De Beers is the world's best-known diamond company and the largest by value. Anglo American owns 85% and the government of Botswana 15%. Botswana supplies around 70% of De Beers' diamonds through Debswana, a 50/50 joint venture. In 2026 Anglo American selected a consortium led by former De Beers CEO Gareth Penny as preferred bidder for its stake, and the sale is still being finalised.

Alrosa, majority-owned by the Russian state, mines the largest volume of diamonds, mostly in Siberia. Its diamonds are under EU, US and G7 sanctions and cannot be sold into Europe.

Rio Tinto was long the third major player, operating Australia's Argyle mine (famous for pink diamonds) and Canada's Diavik mine. Argyle closed in 2020, and Diavik produced its final diamonds in 2026, ending Rio Tinto's 50-year history in diamond mining.

Other significant producers include Endiama, Angola's state diamond company, Burgundy Diamond Mines (Ekati, Canada) and Lucara (Karowe, Botswana).

How does a rough diamond become a polished gem?

A rough diamond becomes a polished gem through five stages (planning, cleaving or sawing, bruting, polishing and grading), a process that can take weeks or months for a single stone.

1. Planning: the rough is scanned in 3D and its inclusions are mapped to find the cut that keeps the most weight and beauty.
2. Cleaving or sawing: the crystal is split, today usually with a laser, into one or more workable pieces.
3. Bruting: the diamond is shaped into its basic outline, such as round or oval.
4. Polishing: facets are ground onto the stone in precise angles to maximise brilliance and fire.
5. Grading: an independent laboratory such as GIA, IGI or Antwerp's own HRD grades the 4Cs (cut, colour, clarity and carat weight) and issues a certificate.

Where are diamonds cut? India, particularly Surat and Mumbai, now cuts the large majority of the world's diamonds. Producing countries such as Botswana and Namibia also require part of their output to be cut locally, so that more of the value stays at home. Antwerp specialises in trading, grading and cutting larger, high-value and complex stones.

What about lab-grown diamonds?

Lab-grown diamonds (Lab-grown diamanten) are real diamonds created in a laboratory rather than in the earth. They are made by HPHT (high pressure, high temperature) or CVD (chemical vapour deposition), which reproduce the conditions in which natural diamonds form. They have the same chemical composition, hardness and brilliance as natural diamonds. The difference is origin, along with price and rarity.

Philippe Harold offers both certified natural and certified lab-grown diamonds, so you can choose based on your budget and what matters most to you.

Why is Antwerp the diamond capital of the world?

Antwerp has been at the centre of the diamond trade for more than 500 years. Today a large share of the world's rough and polished diamonds pass through the city, mostly within a few streets of the Antwerp diamond district beside Antwerpen-Centraal station.

The district brings the whole industry into one square mile:

• Four diamond exchanges (bourses), where traders from around the world buy and sell rough and polished stones.
• Independent grading laboratories, including HRD Antwerp.
• Cutters, setters and goldsmiths with generations of experience.
• Strict oversight: the Antwerp World Diamond Centre (AWDC) and Belgian customs control imports and exports, including Kimberley Process checks.

For buyers, that means one thing: access to an exceptional choice of certified diamonds, close to the source of the trade.

Buying a diamond in Antwerp with Philippe Harold

Philippe Harold is a family-owned jewellery house in the heart of the Antwerp diamond district, now in its fourth generation since 1937. We source certified natural and lab-grown diamonds directly through Antwerp's trade and craft them into engagement rings, wedding bands and fine jewellery.

• Bespoke design: create your own engagement or wedding ring, usually ready about 2–3 weeks after design approval.
• Expert guidance: we'll help you compare stones side by side and explain every certificate.
• Visit or consult online: book an appointment at our showroom, 1st floor, Vestingstraat 36, 2018 Antwerp, or arrange a virtual consultation.

[Explore our engagement rings] · [Discover bespoke design] · [Book a consultation]

Frequently asked questions

Where do most diamonds come from? Most natural diamonds come from Russia, Botswana, Angola and Canada, which together mined about three-quarters of the world's rough diamonds in 2024. Smaller but significant producers include the DR Congo, South Africa, Zimbabwe and Namibia.

How long does it take for a diamond to form? Natural diamonds took anywhere from millions to billions of years to form and reach the surface. Most are between 1 and 3.5 billion years old, so they are among the oldest materials you can wear.

Which country has the best quality diamonds? By average value, Namibia produces the highest-quality diamonds in the world, at about US$417 per carat in 2024. Lesotho, Sierra Leone and South Africa also produce high-value stones. Quality always varies stone by stone, though, so the certificate matters more than the country.

Does Antwerp have diamond mines? No. Belgium has no diamond mines. Antwerp is the world's leading diamond trading centre, where rough and polished diamonds from mines worldwide are bought, sold, graded, cut and certified.

What is the Kimberley Process? The Kimberley Process is an international certification scheme, in force since 2003, that requires every shipment of rough diamonds to carry a government certificate proving it is free from conflict diamonds. It grew out of the July 2000 World Diamond Congress in Antwerp.

Are lab-grown diamonds real diamonds? Yes. Lab-grown diamonds are chemically, physically and optically the same as natural diamonds. The only difference is that they are created in a laboratory in weeks rather than in the earth over billions of years.

How can I be sure my diamond is conflict-free? Buy a certified diamond from a reputable jeweller who can explain its supply chain. Ask for the grading certificate and confirmation that the stone was traded under the Kimberley Process and the System of Warranties.

Is it better to buy a diamond in Antwerp? Buying in Antwerp gives you access to one of the world's largest selections of certified diamonds, independent grading labs and experienced craftspeople in one place, often at more competitive prices thanks to proximity to the trade.

Sources

• Kimberley Process Certification Scheme, Annual Global Summary 2024: production by country (kimberleyprocessstatistics.org)
• Natural Resources Canada, Diamond facts: world production shares, 2024
• National Jeweler and Reuters (July 2026): De Beers sale and ownership
• Mining.com / Northern Miner (2026): Rio Tinto closes Diavik and exits diamonds