How are natural diamonds formed and mined?

9th January 2026 | ROSALYN GOMERSALL

Timeless, inherently rare, and breathtakingly beautiful, it’s no wonder natural diamonds transition seamlessly through every season of life. Long celebrated as symbols of enduring love, beauty, and strength, their inimitable sparkle transforms them into meaningful pieces that can be passed down from one generation to the next. This holds true for everything from eminently wearable diamond earrings to a diamond wedding ring that signifies lifelong commitment. Consider the effortless elegance of a tennis bracelet that will never go out of style, or a diamond necklace destined to be treasured for a lifetime.

If you’re captivated by nature’s most iconic gemstone, understanding how natural diamonds are formed reveals what makes them so coveted.

Shaped by time, immense pressure, and remarkable resilience, a diamond’s journey is nothing short of extraordinary—beginning deep beneath the Earth’s surface and culminating in the brilliance we know today.

HOW ARE DIAMONDS MADE?

Whether it's a diamond ring or pair of sparkling hoops, the natural diamonds in your jewellery begin forming one to three billion years ago, deep within the Earth’s mantle. At depths of approximately 90 to 120 miles, intense heat (over 2,000°F) and extreme pressure cause carbon atoms to bond together, creating the crystal structure we recognise as a diamond.

This atomic arrangement, known as a crystal lattice, is what gives diamonds their exceptional strength and remarkable optical brilliance. Each carbon atom bonds to four others in a precise three-dimensional pattern, forming the hardest known natural material on Earth.

For millions of years, diamonds remain hidden far below the surface. They are only brought closer to the surface through rare volcanic eruptions, which propel them upward at incredible speed through magma channels known as kimberlite and lamproite pipes. Without these powerful geological events, natural diamonds would remain forever out of reach.

Some of the rarest diamonds form through alternative processes. They can develop in subduction zones, where tectonic plates collide and generate extreme pressure, or during meteorite impacts, when sudden heat transforms carbon into diamond. In exceptional cases, diamonds have even formed in space, eventually reaching Earth on meteorites.

WHERE ARE DIAMONDS FOUND?

Natural diamonds are rare, forming only under very specific geological conditions and in locations where volcanic activity brings them close enough to the Earth’s surface to be mined. Today, diamond production is concentrated in a handful of kimberlite-rich regions, where the conditions for diamond formation and accessibility are ideal.

Major Diamond-Producing Countries

South Africa has played a central role in global diamond production since 1869, marking the start of the modern diamond era. Other leading diamond-producing countries include Russia, Botswana, Angola, Canada, the Democratic Republic of the Congo, and Namibia. Together, these nations supply the majority of the world’s natural diamonds.

Supporting countries such as Guinea, Lesotho, Sierra Leone, and Zimbabwe contribute smaller but consistent diamond outputs, sourced through a mix of mechanised mines and artisanal mining operations.

Legendary Diamond Mines

Some of the world’s most famous diamonds have emerged from iconic diamond mines around the globe. Botswana’s Jwaneng and Orapa mines are celebrated for producing high-quality stones. Canada’s Ekati and Diavik mines, where our colourless ARCTIC LIGHT diamonds originate, are recognised for their rigorous environmental standards and responsible mining practices. South Africa’s Cullinan mine is legendary as the source of the largest rough diamond ever discovered.

Global Diamond Supply

Worldwide, fewer than 100 productive diamond mines exist, past or present. Each year, approximately 110–130 million carats of diamonds are mined, yet only about one-third are considered gem-quality diamonds. Larger, high-clarity and colourless diamonds are even rarer, which contributes to their exceptional value and desirability.

HOW ARE DIAMONDS MINED?

Once diamond-bearing rock is identified, natural diamonds are brought to the surface through several mining methods:

Open-pit mining

Open-pit mining is used when diamonds are found near the surface. This method involves removing the overburden, such as any soil, rock and plants, before extracting the valuable diamond-bearing ore below. Excavators then transport the ore to a processing plant where it is crushed and screened to separate the diamonds from the rock.

Underground mining

When deposits lie deeper beneath the earth, underground mining is required to tunnel down to reach the kimberlite pipe. A network of tunnels and shafts provide access to high-quality diamonds that would otherwise remain out of reach, which also allows for minimal surface disruption.

Alluvial mining

Over thousands of years, kimberlite pipes exposed at the Earth’s surface are weathered by wind, rain, and flowing water. As the kimberlite breaks down, rough diamonds are released and carried downstream, forming alluvial deposits. Alluvial mining typically involves redirecting or containing water to access diamond-rich gravel layers. The first diamonds discovered in South Africa originated from were from alluvial deposits.

Marine mining

Marine mining involves recovering diamonds from the seabed, often hundreds of metres underwater. Using ships and specialised equipment, diamonds are extracted from offshore deposits formed where ancient river systems once carried them out to sea. The coast of Namibia is the world’s richest known source of marine diamonds, accounting for over half of the country’s total diamond production.

Artisanal mining

Artisanal mining involves small-scale, labour-intensive operations where individuals or communities collect diamonds using their hands, basic tools and low-tech equipment. Though production is smaller, these efforts are vital to local economies in some regions.

After extraction, rough diamonds are carefully sorted, cut, polished, and graded before becoming the sparkling stones we recognise.

Discover Responsibly Sourced Diamonds at Ernest Jones

At Ernest Jones, we believe that the beauty of a diamond should be matched by the integrity of its journey. As a founding member of the World Diamond Council (WDC), we have been committed to raising standards in the diamond sourcing industry since 2000. All our diamonds are responsibly sourced and comply with the Kimberley Process, helping to reduce the flow of conflict diamonds. Our exclusive, traceable collections – Origin by Ernest Jones, ARCTIC LIGHT and Leonardo Da Vinci Cut – can even be traced back to their country or mine of origin, offering transparency and peace of mind with every diamond.