The Natural Diamond Council has secured two rulings from the UK’s Advertising Standards Authority (ASA) against synthetic diamond retailers over advertising practices deemed misleading to consumers.
On May 13, 2026, the ASA upheld complaints filed against Novita Diamonds and Linjer Ltd for advertisements that failed to clearly identify their products as laboratory-grown diamonds.
According to the rulings, both companies breached the UK Code of Non-broadcast Advertising and Direct & Promotional Marketing (CAP Code). The regulator directed the companies not to repeat the advertisements in the same form and instructed them not to use the term “diamond” in isolation for synthetic diamonds without a clear qualifier such as “synthetic”, “laboratory-grown” or “laboratory-created”.
The complaint against Novita Diamonds related to two Meta advertisements promoting engagement rings and “Premium Diamonds” without identifying the stones as laboratory-grown. The ruling against Linjer concerned two Google advertisements containing the phrase “Discover our brilliant diamonds”.
“This is a victory for consumers,” said Amber Pepper. “It’s vital that consumers can make informed choices in total confidence.”
The ASA referenced the National Association of Jewellers Diamond Terminology Guideline, recognized by UK Trading Standards. The guideline states that authorized qualifiers for synthetic diamonds include “synthetic”, “laboratory-grown” and “laboratory-created”, while terms such as “cultured”, “cultivated”, “real”, “genuine” and “natural” should not be used.
The rulings also clarified that disclosures must appear within advertisements themselves rather than only on linked websites. In Novita Diamonds’ case, the ASA noted that even where the advertisement did not explicitly mention “diamond”, the inclusion of the word within the brand name still required a qualifying description.
David Troostwyk, whose organization jointly filed the complaints, said the decisions should send “a strong message to manufacturers and retailers” regarding advertising compliance.
The Natural Diamond Council noted that the ASA had previously upheld or informally resolved similar complaints involving synthetic diamond advertising claims against Skydiamond, Stephen Webster, Lark & Berry and Idyl in recent years.