Here’s how scientists grow perfect diamonds in the lab

caption
A natural 100-carat diamond. The largest polished synthetic diamond is about 10 carats.
source
Stefan Wermuth/Reuters

Real, or natural, in the vernacular of diamonds, isn’t always better.

While the specter of conflict or “blood” diamonds has largely faded in recent years, thanks to ethical mining practices, international monitoring, and improved certification, natural gems still leave giant holes in the ground and pose a threat to the environment.

Synthetic diamonds are marketed as a solution to customers who are turned off by natural diamonds, all while providing pristine product – and typically priced at 15% to 30% less than similar, naturally forged stones.

That’s partly why a friend of mine, as he relayed in a recent story for Popular Science, proposed to his future wife with a lab-grown diamond.

Here’s how natural and synthetic diamonds differ, where and how they’re grown, and the amazing variety of places they’re found beyond the jewelry store.


Natural diamonds start out as carbon trapped in hunks of rock, called xenoliths, some 100 miles below the Earth’s surface.

source
James St. John/Flickr (CC BY 2.0)

Xenoliths must “cook” at about 2,000 degrees Fahrenheit then ride a spurt of lava to the surface, where the carbon can cool into diamonds at the edges of a carrot-shaped tube.

source
Asbestos/Wikipedia (CC BY-SA 3.0)

Source: LiveScience.com


This is why commercial diamond mines are usually conical pits: Workers excavate walls of minerals (often kimberlite) hunting for diamond-containing xenoliths.

caption
Diavik diamond mine
source
Sergei Karpukhin/Reuters

But beautiful diamonds do not need to be intensively dug out of billion-year-old lava pipes. Since 1954, diamonds have been grown inside laboratories in a variety of colors and purities.

caption
A collection of synthetic diamonds.
source
Reuters/Reuters TV

Source: Popular Science


For growing gemstones, the most popular method is called chemical vapor deposition (CVD), which starts out with a tiny diamond “seed.”

source
Pure Grown Diamonds

Each seed is made of a repeating lattice of carbon atoms — just like all diamonds.

source
steve p2008/Flickr (CC BY 2.0)

The seeds are placed inside a microwave plasma oven. The oven zaps natural gas into a plasma of carbon, which sticks to each seed and slowly builds up a diamond, atom by atom.

source
Pure Grown Diamonds

A company called Pure Grown Diamonds told Business Insider that it can take anywhere from 10 to 12 weeks to bake up a batch of substantially-sized diamonds in its Singapore lab.

source
bark/Flickr

Source: Pure Grown Diamonds


This is why jewelry-grade synthetic diamonds aren’t cheap — and why actor Leonardo DiCaprio and 10 billionaires have invested in Diamond Foundry, which claims it can cut the time to a few weeks.

caption
DiCaprio got involved in the diamond industry after playing a lead role in the 2006 movie “Blood Diamond”.
source
Warner Bros.

Source: Business Insider


Diamond Foundry’s process also uses CVD, though at less pressure and at a higher temperature in a reactor that can reach 8,000 degrees Fahrenheit.

source
Diamond Foundry

Source: Business Insider


After the synthetic diamonds are grown to spec, they’re cut into rough shapes with a high-power laser.

source
Pure Grown Diamonds

Most of the time they come out square to maximize the amount of synthetic diamond.

source
Pure Grown Diamonds

Next, just like natural diamonds, skilled workers polish the synthetic gems for faceting, Pure Grown Diamonds told us.

source
Pure Grown Diamonds

Any of the company’s gems above 1/4 of a carat (a measure of diamond weight) are laser-inscribed with a registry number and graded by their color, cut, clarity, and carat.

source
Francois Lenoir/Reuters

Source: Pure Grown Diamonds


The diamonds are then sold to retail outlets as synthetic, sustainable, and conflict-free diamonds.

source
Pure Grown Diamonds

Outside the jewelry store, you can find cheaper synthetic diamonds everywhere. Like these diamond-encrusted drill bits for powering through glass.

source
Wikipedia

This diamond — a polycrystalline variety that’s a single wafer and made by a company called Element Six— isn’t for engagement rings. But the “super material” may be useful in radar systems, communications devices, and perhaps radio telescopes.

Source: Element Six, Semiconductor Today, Associated Press


Other varieties of diamond, like this flat sheet, can become scratch-free optics that go into lenses, lasers, and infrared cameras.

Source: Element Six


Synthetic diamonds are even making their way into high-end speaker systems as the perfect tweeter material.

Source: Element Six