Deep inside the Earth, where it is dark and incredibly hot and there are intense amounts of pressure, a magical thing happens. These ideal circumstances transform ordinary carbon into something of grand value: genuine diamonds. Dazzling, valuable and timeless, diamonds have a bit of mystery surrounding them. It’s sometimes hard for people to comprehend exactly how clear, brilliant diamonds are formed and extracted from the depths of our dirt-filled Earth. It’s an intricate process, requiring the stars to align perfectly for natural diamond formation—and eventual discovery. Let’s take a closer look at what natural diamonds are and how and where they're formed.
What is a natural diamond?
Natural diamonds are gemstones that form deep in the mantle layer of the Earth, about 100 miles beneath the surface.
The raw diamond formation process does not happen overnight. Or even over a human’s lifetime. It takes many millions of years for the pressure and temperature within our planet to transform carbon into a diamond. After many years in this intense environment, diamonds withstand two crucial elements essential for diamonds to form: rapid cooling and reduction in pressure. Without these, the structure formed by the carbon would be different, resulting in a softer granite instead of a diamond. This cooling allows the diamond’s structure to form with its atoms bonded the same way in all directions, creating natural diamonds—the hardest material on the planet.
Consisting of 99.95% carbon, most diamonds contain trace amounts of other elements, such as nitrogen, boron or hydrogen. These other elements aren’t technically part of the diamond’s chemical makeup. Instead, they are atoms trapped within the diamond’s crystalline structure. These atoms can change the way light is absorbed or reflected by the diamond, influencing the diamond’s color.
Where are diamonds found?
While it's true that the essential ingredients for diamond formation can be found across the planet, the specific conditions required are incredibly rare and demanding. Diamonds typically form around 90 to 120 miles beneath the Earth's surface. These extreme environments are primarily found in ancient, stable regions of the Earth's crust known as cratons.
Furthermore, once diamonds do form in the Earth’s crust, they still need to be transported closer to the surface through rare volcanic eruptions that produce structures called kimberlites or lamproites. Miners target these structures when searching for diamonds. Because these geological conditions are relatively uncommon, diamond deposits are concentrated in only a few specific regions where they occur more often.
Places around the world where diamonds are commonly found
Diamond production occurs primarily in two "bands" around the Earth—the Northern band and the Southern band. Diamond-producing countries in the Northern band include Canada, Europe, and Asia, while the Southern band consists of countries like Botswana, South Africa, Namibia, and Australia. Some countries in the "center band" between the Northern and Southern bands, are known for producing diamonds as well. Let’s take a closer look.
Southern Africa (South Africa, Botswana, Angola, Democratic Republic of Congo)
Southern Africa is renowned for its rich diamond deposits, particularly in kimberlite pipes. With decades of success in the industry, South Africa’s total carat production was about 6 million in 2023. The largest gem-worthy diamond ever found, the Cullinan Diamond, was found in South Africa’s Premier mine in 1905.
Europe and Asia
This area boasts of being one of the (if not the) largest diamond-producing countries in the world, accounting for 32% of global production. The Siberian region contains vast diamond fields. Like the ones in Southern Africa, diamonds in this area are also found in kimberlite pipes.
Canada (Northwest Territories)
Canada's diamond industry is relatively young but has rapidly grown in importance, with Canadian diamond exports expected to grow 12,386% between 2023 and 2027. Originating from kimberlite pipes, Canadian diamonds have a reputation for being of exceptionally high quality, and their mines meet some of the world’s highest environmental standards.
Australia
Australia's diamond deposits are primarily found in lamproite pipes, which are similar to kimberlites but have a different mineral composition. The largest diamond ever found in Australia was mined at the Merlin Mine, Northern Territory, in 2003 and weighed 104.73 carats. Australia's now-closed Argyle mine was operational for 37 years and was once the world's largest diamond-producing mine by volume. The country is one of the leading colored diamond producers in the world, known for its stunning pink, purple, and red gems.
Namibia
Located on the southwest coast of Africa, Namibia’s diamond wealth is concentrated in coastal alluvial deposits. These deposits formed when diamonds, eroded from their original kimberlite sources, were transported by rivers and deposited along the coastline. In 2022, the country exported more than $940 million of diamonds.
Brazil
South America also boasts diamond-rich regions, with Brazil being a prominent example. Brazil has been a diamond-producing powerhouse for centuries. Brazil’s mining has occurred among independent miners sifting through riverbeds. While its alluvial deposits amongst ancient river systems continue to be a source of diamond finds, efforts have been made to locate the kimberlite origin site to set up mines in recent years.
Four fast facts about diamond formation
Diamond formation is so intriguing! Here are four more fun facts about diamond formation.
- A tale as old as time: Diamonds are ancient relics, some even older than dinosaurs. Diamonds form slowly, atom by atom, with some dating back more than 3 billion years.
- Even deeper diamonds? Super deep diamonds are formed at extraordinary depths, up to 500 miles below the Earth's surface, in the depths of the upper mantle. These diamonds contain unique mineral traces that provide evidence of their deep origin. Their formation process is complex and still being studied. Due to their rare and distinctive characteristics, super deep diamonds hold significant scientific value for understanding the Earth's interior.
- Raining diamonds? Believe it or not, scientists theorize that it might "rain diamonds" on planets like Neptune and Uranus. The extreme pressure and temperatures on these gas giants could transform methane into diamonds. Send some of that rain our way, Neptune!
- Diamond's best friend (or enemy): Yes, even diamonds have frenemies. While heat is necessary for their formation, too much heat can actually destroy a diamond. This is why the specific conditions for diamond creation are so precise. Call it a love-hate relationship.
Protect your diamonds with jewelry insurance from Jewelers Mutual
Natural diamonds aren’t formed overnight, but they can certainly be lost, damaged, or stolen overnight! Before that happens, consider insuring your precious diamonds or other valuable jewelry with a personal jewelry insurance policy from Jewelers Mutual. A personal jewelry insurance policy has certain benefits over insuring your jewelry under your homeowners insurance policy. Click the link below to check your rate from Jewelers Mutual.
