What to make of the Sky Diamond?

F Scott Fitzgerald, best known for The Great Gatsby, published a novella in 1922 called The Diamond as Big as the Ritz. It tells the story of a family who own a mountain that is made entirely of diamond, and the lengths they go to in order to protect it. One of the ironies of the story is that while they possess something inordinately valuable, it is only worth anything if diamonds remain rare. If the world knew that there was a mountain-sized diamond out there, the value of all existing diamonds would collapse.

I was reminded of this story by the news that a company has made diamonds out of carbon in the air, indistinguishable from the ones extracted from the ground but with negligible environmental impact. And if you can make diamonds out of the air, what is that diamond worth?

Manufactured diamonds aren’t a new thing. As soon as scientists estabished that diamonds were carbon, people have been trying to make them – a less dubious form of alchemy. Methods were developed from the 1940s onwards, with various industrial applications. Making actual gemstones is more recent. It only became commercially viable quite recently, triggering panicked lobbying efforts from established firms such as De Beers to protect their ‘natural’, ‘real’ diamonds. They have failed, not least because ‘real’ means extracted from the dirt and plundered from Africa. From a small base, manufactured diamonds are growing fast and prices are falling.

What’s different about Sky Diamonds is that the idea has come from carbon capture first, another leftfield idea from a man with a history of them, Dale Vince of Ecotricity. “Some years ago, I was thinking about the concept of geoengineering as a way to extract carbon from the atmosphere” he says in his new autobiography, which I’m reading at the moment. “That led me to think about how to store that carbon, and to the simple thought that the most permanent, enduring form of carbon – the toughest of all – is a diamond. I wondered if it might be possible to take carbon from the atmosphere and turn it into diamonds.”

The process they use takes a diamond ‘seed’, and grows a diamond from it using layers of carbon vapour in a furnace. They are ‘sky diamonds’ because all the key elements come from the sky – CO2, hydrogen electrolysed from rain water, and the energy to run the furnace from wind and solar power. The company aren’t making any big claims about how much carbon they can lock away: they describe it as ‘modest’. But the process is being reported as carbon negative and zero impact.

Compared to the huge impact of mined diamonds, it’s a dramatic improvement. It’s a big step forward on the ethical front too, and a growing number of buyers are choosing manufactured diamonds for ethical reasons. And perhaps one of its biggest contributions will turn out to be in marketing. The idea of ‘sky diamonds’ frames manufactured gems in a new way, highlighting the benefits of the process rather than being somehow embarassed that they’re not ‘real’ ones dragged out of the ancient muck. That might preserve the romance that many people find in diamonds, and take it in a new direction for the 21st century.

So it will be interesting to see what becomes of Sky Diamonds, and whether it can actually put a dent in the polluting and exploitative industry. Dale Vince seems to suggest that’s where he wants to go: “This is green technology as it needs to be – sustainable, ethical and fun. Our next campaign will be to end diamond mining.”

• I’ll review it shortly, but if you’re so inclined you can get Vince’s book Manifesto: How a maverick entrepreneur took on British energy and won from Earthbound Books.