UK Watchdog Orders Retailers to Withdraw Misleading Synthetic Diamond Ads

The Natural Diamond Council (NDC) has welcomed two rulings by the UK’s Advertising Standards Authority (ASA) against jewellery retailers accused of misleading consumers by failing to clearly identify lab-grown diamonds (LGDs) in advertisements.
The ASA upheld complaints against UK-based Novita Diamonds and Hong Kong-based Linjer Ltd, ruling that their adverts breached the UK Code of Non-broadcast Advertising and Direct & Promotional Marketing. The regulator directed both companies not to repeat the advertisements in their existing form and instructed them to clearly qualify synthetic diamonds with terms such as “synthetic” or “laboratory-created”.
According to the NDC, the rulings reinforce the need for transparency in how synthetic diamonds are marketed to consumers. Amber Pepper, CEO of the Natural Diamond Council, said the decisions marked “a victory for consumers” and stressed that buyers should be able to make informed purchasing decisions with confidence.
The complaint against Novita Diamonds related to Meta advertisements promoting “ready-to-ship engagement rings” and “premium diamonds” without clarifying that the products were laboratory-grown. Meanwhile, Linjer’s Google advertisements used the phrase “Discover our brilliant diamonds” without adequate disclosure.
The ASA referenced the National Association of Jewellers’ Diamond Terminology Guideline, which specifies that authorised qualifiers such as “synthetic”, “laboratory-grown” or “laboratory-created” must accompany references to synthetic diamonds. The guideline also discourages terms including “cultured”, “real”, “genuine”, and “natural” for laboratory-grown products.
The regulator further clarified that disclosure must appear directly within advertisements and not solely on linked websites. It also noted that even if the word “diamond” appears only in a brand name, a clear qualifier is still required where synthetic products are involved.
The latest rulings add to a series of successful challenges by the NDC against synthetic diamond advertising practices in recent years, including complaints involving Skydiamond, Lark & Berry and Stephen Webster.