It takes a million years for a diamond to form in the earth, but mere months for a diamond that is chemically identical to be grown in the pristine conditions of a laboratory. Currently, these man-made diamonds – known to some as above-ground gems – account for just 1 per cent of the US$14 billion global rough diamond market (according to a 2016 Morgan Stanley report), so they are still a niche product, but one that is set to grow. This year, both Swarovski and Lightbox (part of the De Beers Group) are debuting lab-grown gems.

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Swarovski has always invested in “conscious luxury”. Sharing these values is movie star and environmental campaigner Penélope Cruz, who collaborated with Nadja Swarovski on a special new Atelier range. “The relationship gives me the opportunity to shine a light on conscious luxury and create products that have a positive impact,” explains Cruz. “Sustainability should be the number one priority right now.”

The collection has immediate red-carpet appeal with matching suites of jewellery featuring lab-grown diamonds, rubies and sapphires manufactured with renewable energy and set in Fairtrade gold. Cruz’s favourite piece is a diamond and ruby necklace that has undeniable Hollywood allure. “Some of the pieces have a very vintage feeling and I always go back to that – they are timeless.”

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De Beers, meanwhile, is giving credibility to a product that it claimed for years is not the real thing. Its lab-grown gems, originally developed in the 1950s for industry, are cut like a diamond and shine like a diamond. They are now marketed as a new fashion jewellery label, called Lightbox, of (relatively) low-budget gems with a fun, playful mass-market appeal. There is no pretence about this being promoted to the conscious consumer as an alternative to natural gemstones and the gems identifiable as non-mined. Nevertheless, they will partially offset the power needed to create the gemstones with renewable energy.

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