The UK Advertising Standards Authority (ASA) has ruled against lab-grown diamond retailers Novita Diamonds and Linjer after finding that advertisements failed to make clear that the diamonds being promoted were laboratory-grown rather than natural.
The complaints were brought by the Natural Diamond Council (NDC) and the London Diamond Bourse (LDB), with the ASA concluding that both companies breached UK advertising rules.
Advertisements Found to be Misleading
The rulings relate to online advertisements published in January 2026.
In Novita Diamonds’ case, the ASA assessed two paid-for Meta advertisements. One featured the text “Novita Diamonds ready-to-ship engagement rings 1-10 days”, while another included video footage of diamond rings alongside wording such as “premium diamonds”.
Novita argued that its advertising did not state or imply that the diamonds were mined or natural. The company also maintained that lab-grown diamonds meet the scientific and gemmological definition of diamond because they share the same chemical composition, crystal structure and physical properties as mined diamonds.
The ASA acknowledged those similarities but concluded that the distinction between natural and synthetic diamonds was material information for consumers.
In its ruling, the regulator stated: “Neither of the ads included an explicit qualification that Novita Diamonds were synthetic, laboratory-created, or similar, nor was there anything within their content that made clear they were synthetic. We therefore considered that consumers would not be aware from the ads that the diamonds were synthetic diamonds.”
The regulator also noted that consumers were directed to information on Novita’s website explaining that the diamonds were synthetic, but said this information should have been included within the advertisements themselves.
Novita has since amended the advertisements to include the word “lab” before “diamonds”.
Linjer Advertisements Also Ruled Against
The ASA also upheld complaints against Hong Kong-based jewellery retailer Linjer over two Google advertisements.
One advertisement included the phrase “Discover our brilliant diamonds” alongside images of rings featuring colourless gemstones. Another promoted jewellery described as “sustainable” with “ethically sourced gemstones”.
Linjer told the ASA it had not realised the advertisements breached the rules and said it would work with its advertising agency to ensure appropriate terminology is used in future campaigns.
Addressing the wording used in the advertisement, the ASA said: “We understood that ‘brilliant’ described a type of diamond cut, but we did not consider the average consumer would have been aware of that meaning and, in that context, we considered they were likely to take ‘brilliant diamonds’ to refer to diamonds generally.”
The regulator added: “We considered that whether a diamond was natural or synthetic would be a key consideration for many consumers and was therefore material information.”
Requirement for Clear Qualifiers
The ASA ordered both companies not to run the advertisements again in their current form and instructed them to use clear and prominent qualifiers when marketing synthetic diamonds.
The ruling aligns with UK industry guidance, including the National Association of Jewellers’ Diamond Terminology Guideline, which requires terms such as “laboratory-grown”, “laboratory-created” or “synthetic” to accompany references to man-made diamonds.
The Novita decision also indicates that advertisers may be required to include a qualifier when the word “diamond” appears as part of a brand name, not only in product descriptions.
Industry Response
Following the rulings, NDC chief executive Amber Pepper said: “It’s vital that consumers can make informed choices in total confidence.”
She added: “This is not the first time we have successfully challenged advertising that blurs the distinction between mass-produced products grown in a factory and products of nature formed deep in the earth over billions of years.”
London Diamond Bourse president David Troostwyk said: “These rulings should send a strong message to manufacturers and retailers. Misleading practices exploit the timeless value people associate with natural diamonds to unduly benefit companies at the expense of consumers. We hope the message is now cutting through that irresponsible advertising will not be tolerated.”
What the Rulings Mean for Jewellers
The decisions reinforce the ASA’s position that the origin of a diamond must be disclosed clearly in advertising, rather than only later in the purchasing journey. For jewellery retailers and suppliers marketing lab-grown diamonds, the rulings underline the need to review advertising, social media content and paid search campaigns to ensure recognised terminology is used consistently.
