Following a complaint filed by the Natural Diamond Council (NDC), ASA investigated an advertisement from February 2023 by Skydiamond. The ad touted claims such as "Say hello to the world’s first and only diamond made entirely from the sky" and "We make diamonds using four natural ingredients, the sun, the wind, rain and something we have too much of, atmospheric carbon." It also asserted that the company's jewellery featured the world's "rarest diamonds." The NDC challenged whether these statements adequately conveyed that Skydiamond was selling lab-grown diamonds, not natural ones, as per the ruling on April 10.

Owned by Dale Vince, founder of energy firm Ecotricity, Skydiamond argued that its visuals and information sufficiently indicated that its product wasn't mined and thus didn't necessitate terms like "synthetic" or "laboratory grown." They cited a 2018 ruling by the US Federal Trade Commission (FTC) asserting that "a diamond is a diamond" regardless of its origin, clarifying that the term "diamond" solely denotes the object and doesn't specify its source.

However, ASA found Skydiamond's marketing to be misleading, as it omitted or obscured crucial information. Additionally, a survey of over 2,100 UK adults revealed that 25% were unaware of the existence of man-made diamonds.

The ASA ruling emphasized that consumers could interpret the term "diamond" as naturally occurring crystallized carbon, and while some might know about synthetic diamonds, many wouldn't. The distinction between natural and synthetic gemstones was deemed crucial information for consumers.

Therefore, ASA directed Skydiamond to refrain from using terms like "diamonds," "diamonds made entirely from the sky," and "skydiamond" without clear qualifiers like "synthetic," "laboratory-grown," or "laboratory-created." Moreover, the claim of "real diamonds" for synthetic diamonds was also deemed inappropriate.

Alan Cohen, co-president of the London Diamond Bourse (LDB), praised the ruling for safeguarding British consumers from deceptive marketing of synthetic diamonds. He expressed hope that such practices would cease and called for scrutiny of eco-friendliness claims in the future.