In addition to cost savings and supposed environmental benefits, lab-grown diamonds have the same chemical and physical properties as mined diamonds

Alexander Weindling has a fading, black-and-white framed photograph on the desk of his New York City office. It’s of his grandfather, wearing a hat and suit, posing more than a century ago with some of the workers of a diamond mine he oversaw in what was then known as the Belgian Congo.

The mining of diamonds in Africa led to a human rights disaster from colonial times onwards and Weindling, a third-generation diamond and jewelry merchant, uses the incongruity of this photo in the white minimalism of his Tribeca office as a mental spur. That era of diamond mining was “so devastatingly ugly Isis will start looking like good guys,” says Weindling. “It was dreadful. It was criminal. It was unforgivable.”

Weindling reluctantly joined the family diamond business and rose through its ranks, learning about cutting and distribution. He then left in 2012 to co-found Clean Origin, a company that sells laboratory-grown diamonds via the internet. This, Weindling contends, will be his path to redemption as well as helping address the greatest challenge of the modern era – the climate crisis.

Facebook Twitter Pinterest Lab-grown diamonds as they are growing in a plasma reactor. Photograph: Lionel Bonaventure/AFP via Getty Images

“We all talked a good game, us baby boomers,” says Weindling, who is wearing a white hooded sweatshirt with the words ‘OK Boomer!’ inscribed on it multiple times. “We talked a good game, but we didn’t deliver on it. I want to end my life with clean hands. I was so conflicted in so many ways and I’d like to do something constructive for the world.”

Diamond mining’s history of plunder and unethical work practices were followed by fresher concerns that “blood diamonds” were being used to fund military actions in war zones. The diamond industry has for the past two decades banished this blight through a certification scheme that has largely stamped out unethical trading.

But now pressure over the climate crisis is beginning to grow from campaign groups and a new generation of diamond buyers concerned about the environment. The full toll in planet-warming emissions from the mining and transportation of diamonds has yet to be fully quantified, but for Weindling the equation is clear.

On his computer, Weindling brings up a picture of Mir mine, an enormous gaping hole 1,200 metres across in eastern Siberia where diamonds have been mined since the 1950s. A town perilously perches near the edge of this huge open pit.

Facebook Twitter Pinterest A view of a kimberlite pipe of the Mir diamond mine in eastern Siberia. Photograph: Alexander Ryumin/TASS

“Do you want to tell me this is a good thing?” Weindling asks, rhetorically. “I don’t need science to tell that [lab-grown diamonds] is less bad than that. My eyes tell me that’s a lot worst for our planet. We don’t need to dig these huge holes in the earth any more that are visible from space. We used to hunt whales. We don’t do that any more do we?”

Weindling and a growing number of lab-grown diamond sellers are betting that the upcoming generation of soon-to-be-weds will happily switch from traditional mined diamonds when making their major ring purchase. Weindling pulls up figures showing growing numbers of people are happy to buy their ring online, too, but admits there is a generational gap. “This Gen Z, they are really savvy, they have bullshit meters,” he says. “That said, nobody over 50 will accept a lab-grown diamond – ‘oh don’t give me one of those fake things.’”

Lab-grown diamonds have the same chemical and physical properties as naturally mined diamonds, with even industry experts unable to tell the difference optically. The main giveaway is an “LG” inscribed at the base of the stone.

Diamonds are formed naturally through a combination of heat, pressure and time, growing deep underground until deep-set volcanic eruptions bring them closer to the surface, ready to be excavated. Lab-grown versions recreate this using a fragment of diamond in a sealed chamber which is heated to extreme temperatures - “you heat it to the temperature of the surface of the sun, not the interior of the sun,” Weindling explains – and filled with various gases that add layers to the diamond over a number of days.

The results look remarkably authentic to a layperson. The Federal Trade Commission (FTC) ruled in 2018 that lab-grown diamonds are included in the same definitional universe as mined diamonds but warned against the use of terms like “natural” in marketing that confused the two categories.

Weindling casually hands over an enormous nine-carat cushion cut diamond ring that would be of such rarity if found naturally that it would auction for $5m or $6m. “I’d sell you that for $200,000 very happily,” Weindling says.

“If you’ve ever seen a woman’s face when she puts a diamond on her ring for the first time … God willing if they get pregnant, and now they don’t have that slim body and they’re a little nervous, and they look at that ring, that’s really important,” Weindling adds. “We can’t rip that out of society. However, we can do a lot better in servicing that need without committing this kind of villainy to the planet.”

Facebook Twitter Pinterest Miners pan for diamonds near Koidu in north-eastern Sierra Leone in 2004. Photograph: Ben Curtis/AP

The cost savings, as well as the supposed environmental benefits, are well targeted for a generation struggling with debt and the looming horrors of the climate crisis. In response, the established diamond industry has sought to head off this threat by challenging the idea that it is ruinous for the climate.

De Beers, the world’s largest diamond producer, announced plans in 2017 to operate a carbon-neutral mine and pointed out that the FTC has warned lab-grown diamond sellers over the veracity of their environmental claims.

Diamonds are grown in labs in countries including China, Singapore and the US, places that lean heavily upon fossil fuels for energy. The huge amount of power needed to create a diamond can lead to a significant output in carbon pollution if the energy source is dirty, a point made in a 2019 Trucost report which found that, on average, greenhouse gas emissions are three times greater for lab-grown diamonds than their mined counterparts.

“The majority of claims that lab-grown diamonds are more ethical or environmentally friendly do not appear to be based on any discernible ethical or environmental benefit; they simply rely on using outdated or inaccurate perceptions of the natural diamond sector as a point of comparison,” said a De Beers spokesman, who also pointed to the various economic benefits the industry has brought to countries such as Botswana.

The Trucost report, however, was produced on behalf of the Diamond Producers Association, a trade group of diamond miners including De Beers. “The report makes a lot of assumptions, it doesn’t look at the full life cycle of mines, the energy use of exploration and so on – once you consider that then the impact is enormous,” says Saleem Ali, a minerals expert at the University of Delaware.

“There is a place for mined diamonds because they provide a lot more jobs than lab-grown. But I’d venture to say the environmental impact is far greater for mined diamonds. If you grow a diamond you can situate the lab wherever you want, move it to Norway and use hydropower perhaps. You can’t do that with a mine.”

Ultimately, the battleground will be one of marketing. The mined industry-backed “Real is rare” advertising campaign seeks to present diamonds as a sort of fairytale, one that values authenticity and uniqueness. Lab-grown diamonds, by their nature of production, do not fit this industry image of exclusivity.

“One was manufactured in a laboratory and one was formed in the earth over billions of years, so there is a significant difference in value,” says Cathleen McCarthy, founder of the Jewelry Loupe blog. “I would hope the public sees that difference, because it should be reflected in the price they pay.”

Another jewelry blog influencer, Liza Urla of Gemologue, says most aficionados enjoy lab-grown diamonds for everyday, casual uses but items such as engagement rings are a different matter. “Only the real deal will do because a true diamond holds its value,” she says.

Perceptions can shift, however, and the world of diamonds could well be upended by new environmental norms.

“I just want to give people choice. You want to marry a gerbil? Marry a gerbil. God bless,” says Weindling. “I wasn’t here to judge other people, but I can judge myself very harshly. I won’t touch a mined diamond. I have one left, it’s the one I gave my wife 20 years ago. It’s for sale. If you want to buy it, just make me an offer.”