Besides its hallmark shine, part of a diamond’s appeal is the awe-inspiring natural journey it takes from its formation to being adorned on your piece of jewelry.
Natural diamonds form over billions of years under extraordinary conditions deep within the Earth’s crust, and it is this journey to the surface that makes them one of Earth’s rarest treasures.
At Paul’s Jewelers, we understand that jewelry carries deep meaning. While the sentimental value of each piece is clear, the story behind the diamond itself is often overlooked.
In this article, we’ll walk you through the journey of a diamond—from the Earth to our showroom—so you can appreciate these extraordinary stones on an even deeper level.
Diamond Origins
Diamonds are made out of carbon, one of the most common elements on Earth. What makes carbon actually turn into a diamond, though, are extreme external conditions.
Far deep underneath the Earth in the mantle (approximately 90–120 miles beneath the surface), carbon is subjected to extraordinary heat and pressure.
It’s here where temperatures reach above 2,000°F (1,100°C) and pressure reaches more than 700,000 pounds per square inch.
Under intense pressure within the Earth, carbon atoms bond strongly in all directions, forming a rigid three-dimensional lattice structure. This contrasts sharply with graphite, where carbon atoms bond in flat sheets that stack loosely, making graphite soft.
This atomic structure is what makes carbon into diamonds, giving diamonds their unmatched hardness and ability to reflect light.
This process takes place slowly, over one to three billion years. Layer by layer, diamonds grow as carbon atoms continue to lock into place within the lattice.
Over immense spans of time, these crystals grow large enough to become the rough diamonds that are eventually brought closer to the surface through a separate process.
Note, this geological journey is also what separates natural diamonds from their lab-grown counterparts. Lab diamonds are virtually identical to their mined counterparts - physically, optically, and chemically.
That said, the formation of lab-grown diamonds requires environments that mimic these same conditions. With modern technology, these conditions can be made within a chamber, and diamonds can be synthetically created within a matter of weeks.
Natural diamonds, by contrast, are true relics of Earth’s past—billions of years in the making, shaped by forces that no lab can fully recreate. This natural rarity is what gives natural diamonds their value.
The Role of Kimberlite and Lamproite Pipes
Forming deep underground is only the first step in a diamond’s journey. Without a way to reach the surface, they could never be mined and would remain locked in the Earth’s mantle forever. What brings diamonds to the surface to be mined lies in volcanic activity.
Millions of years ago, deep-source volcanic eruptions carried diamonds upward in fast-moving magma. These eruptions weren’t like the ones we see today—they originated much deeper in the Earth and traveled at super-fast speeds. As the magma surged toward the surface, it tore through the mantle, pulling diamonds along with it.
When these eruptions cooled down and solidified, they left behind vertical columns of volcanic rock called kimberlite pipes, and less commonly, lamproite pipes.
Diamonds became trapped within these formations, which remain the primary sources for mining today.
The speed of the eruption was critical. If the ascent had been slower, the diamonds would have lost their structure and reverted to graphite. The rapid rise preserved them in their crystalline form, allowing them to survive intact for millions of years near the surface.
Over time, natural erosion spread some diamonds away from their original volcanic hosts. Rain, rivers, and shifting soils carried them into alluvial deposits—riverbeds, coastlines, and sediment layers—where humans first discovered them long before modern mining.
Where Diamonds Are Found Around the World
Modern mining takes place in regions where those ancient volcanic events occurred. Some of the most notable mines include:
- Jwaneng Mine, Botswana – One of the richest diamond mines in the world.
- Cullinan Mine, South Africa – Known for producing the Cullinan Diamond, the largest rough diamond ever discovered.
- Diavik and Ekati Mines, Canada – Located in the Northwest Territories, producing exceptional quality diamonds under extreme conditions.
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Argyle Mine, Australia – This mine was recently closed (2020), but it was once a leading source of rare pink and champagne-colored diamonds.
Each of these mines reflects a unique geological story, yet all connect back to the same process: carbon transformed under heat and pressure, carried upward by volcanic eruptions, and uncovered by human hands.
From Rough Crystal to Finished Gem
Freshly mined diamonds don’t look anything like the polished gemstones you see in jewelry. They start as rough crystals, and only about 20% of what’s mined is suitable for fine jewelry. The rest is used for industrial purposes (cutting instruments, grinding tools, etc.).
The path from rough stone to finished piece involves several steps:
- Sorting and Evaluating: Rough diamonds are separated by size, shape, and quality.
- Cutting: Experts decide how to cut each stone to balance its potential appearance with weight. Precision matters—cut is the biggest factor in a diamond’s sparkle (learn more in our Diamond Cut Guide).
- Polishing: Facets are polished to maximize brilliance, fire, and scintillation.
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Grading: Once finished, diamonds are evaluated on the 4Cs—cut, color, clarity, and carat.
This process is where human craftsmanship transforms a billion-year-old crystal into the centerpiece of an engagement ring, pendant, or family heirloom.
Why the Diamond Story Matters
Understanding how diamonds form adds depth to their beauty. They are more than gemstones; they represent rarity, strength, and endurance.
This is also what makes natural stones different from those that are lab-grown. While both share the same physical and chemical properties, natural diamonds are finite. They come from geological processes that happened billions of years ago and cannot be repeated. That rarity adds to both their sentimental and lasting value.
For couples choosing an engagement ring or families preserving a legacy piece, this story is part of what makes a natural diamond so meaningful.
If you’re in the market for a diamond piece, we warmly invite you to our Milwaukee showroom. We’ve been helping clients in the city and beyond with their jewelry journey for the past five decades. Whether you’re looking to repair a piece or are looking to create your next custom jewelry masterpiece, we stand by to help you on your jewelry journey.
