What Is a Natural Diamond?

In the more than 500 years since Archduke Maximilian of Austria presented Mary of Burgundy with the first diamond engagement ring, the stone has come to symbolize purity, faithfulness, love, and luxury. Still the most popular option for an engagement ring today, diamonds are incredibly strong and incredibly rare. But understanding why they’re so valuable—and what to look for when you’re shopping for one—is key to choosing the stone that’s right for you.

“The most important thing to remember when buying a piece of diamond jewelry is to not rush the process,” says Kristina Buckley Kayel of the Natural Diamond Council. “It's paramount to take your time to research and know exactly what you're buying and where it’s coming from. A natural diamond’s character is as special and as rare as that of the person wearing it.”

Ahead, experts share everything you need to know about natural diamonds, from how they're formed (and found!) to understanding their long-term value—and how to choose one that will look as lovely now as it will in 50 years.

How Natural Diamonds Are Formed

Natural diamonds found underground are a “crystalline form of pure carbon that’s formed by the extreme heat and pressure of the earth,” says Kayel. The stones are known for their durability, rarity, and sparkle. “Natural diamonds are the hardest naturally occurring substance, and formed deep within the earth 1 to 3 billion years ago,” says Kayel. “Natural diamonds are the oldest thing you will ever touch—let alone own.”

Colored diamonds can also be formed underground; the hue changes based on other elements present as the carbon crystallized. “During a diamond’s formation, when carbon atoms bond together, coupled with the trapping of non-carbon atoms or if there are changes in pressure, this can alter the stone,” says Kayel. “This results in diamonds of nearly every color in the rainbow, otherwise known as ‘fancy colored’ diamonds.” 

While brown and yellow are the most common fancy colors, says Olivia Landau of The Clear Cut, the stones also may come out blue, green, pink, or red. “A natural blue diamond is formed in an area with trace elements such as boron,” says Landau. “This is also true for green diamonds, as they are a result of being formed near a uranium deposit with radiation.”

The Unique Attributes of Natural Diamonds

Diamonds are graded according to their cut, color, carat weight, and clarity—the four Cs. The higher a stone scores in each category, the more valuable it is. But the same imperfections that might make a diamond more financially accessible give it a look all its own. “It’s essential to look beyond the four Cs and consider the fifth C: character,” says Kayel. “Due to their rarity and ancient and natural formation, every diamond’s character is unique.” 

Landau also looks for the one-of-a-kind elements in each stone. “Although there can be defects, I believe that these are actually the natural fingerprints or ‘birthmarks’ of the diamond and can result in some of the coolest stones,” she says. “The inclusions that get caught in the diamond over the formation process that takes billions of years give each one their own unique story, and is what makes them so special.”

Why Natural Diamonds Are So Valuable

Natural diamonds are still incredibly rare—especially relative to lab-grown diamonds, which can be produced in “unlimited quantities” in only a few weeks, say the experts. “Natural diamonds are a rare and finite resource that take billions of years to create, and because there are no new diamonds currently being formed, they are a true rarity,” says Landau.

Kayal visualizes it this way: “The annual recovery of all natural diamonds 1-carat and above can fill just one exercise ball,” she says. “Of the diamonds that are being mined today, only about 50 percent are thought to be high enough quality to be sold on the diamond market, making them an incredibly valuable commodity.”

What to Look for When Buying a Natural Diamond

When shopping for a diamond, Landau recommends looking for stones with cut, color, clarity, and carat ratings certified by the Gemological Institute of America (GIA)—and finding a jeweler you trust. “No two diamonds are the same, and all diamonds are graded by humans, so it is more of an art than a science,” she says. Kayel recommends paying close attention to the way a piece of jewelry is advertised. “Lab-grown diamond’s must be disclosed as such and cannot simply be called a ‘diamond,’” she says. “The word ‘diamond’ alone implies that it’s a natural diamond.”

Ethical Sourcing

As the diamond industry has matured, increased oversight has counteracted the ethical issues that previously plagued mining processes. “It is very rare to find a diamond that isn't ethically sourced,” says Landau. The Kimberley Process, developed by the United Nations and the World Trade Organization, regulates the diamond trade and authenticates the ethical sourcing of each stone. More than 80 countries are part of the process, says Kayel, under which “all rough diamond trade is strictly regulated to ensure it is conflict-free.” The industry is also implementing blockchain technologies to help customers trace the path of their diamond, from mine to proposal. 

Sustainability

Increasingly ambitious sustainability initiatives include companies like the De Beers Group and Rio Tinto setting carbon neutrality timelines. “The diamond industry actively protects the biodiversity surrounding each mine, covering an area four times larger in size than the land they use,” says Kayel.

Heirloom Quality

Buying a natural diamond now—before the supply drops even more dramatically, likely in the next two to three decades, says Landau—means you’re investing in an asset that will appreciate in value (both sentimental and financial). “Natural diamonds hold their value,” says Landau. “Heirloom diamonds are the ultimate form of sustainability, because they are recycled and passed down through generations.”