Ad description
Two paid-for Google ads for Linjer, a jewellery retailer, seen on 14 January 2026:
a. The first ad stated “Anniversary Sale Up to 20% Off - Linjer Sustainable Jewelry [sic]”. Further text underneath stated “Celebrate 11 years of craftsmanship with 20% off jewelry [sic] you'll treasure forever. Invest now, wear forever. Discover our brilliant diamonds […]”. The ad included an image showing two gold rings with gemstones.
b. The second ad stated “Everyday Fine Jewellery - Linjer Sustainable Jewellery”. Further text underneath stated “Invest now, wear forever. Discover our brilliant diamonds […] Shop today for our unique jewellery with ethically sourced gemstones and timeless…”.
Issue
The Natural Diamond Council and the London Diamond Bourse, who understood the products were synthetic diamonds, challenged whether the ads misleadingly implied they were natural diamonds.
Response
Linjer Ltd did not realise that their ads breached the Code. They said they would work with their ad agency to include language around the diamonds being lab grown to their Google ads, and had implemented internal checks to ensure the terminology was consistently applied going forward.
Assessment
Upheld
The ads included the claim “brilliant diamonds”. Ad (a) also included an image of two rings that had clear gemstones. The ASA considered that consumers would understand the word “diamond” in isolation to mean a naturally occurring mineral consisting of crystallised carbon. 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. We considered that while some consumers may have been aware that synthetic diamonds could be manufactured or created in a laboratory, many would not. We also understood that although synthetic diamonds had the same chemical and physical properties as natural, mined diamonds, there were differences in their future value. We also considered that whether a diamond was natural or synthetic would be a key consideration for many consumers and was therefore material information. We therefore considered that ads for synthetic diamonds needed to make clear the nature of the product in order to avoid misleading consumers.
The National Association of Jewellers’ “Diamond Terminology Guideline”, which had the status of ‘Assured Advice’ from Trading Standards, stated that when referring to synthetic diamonds, a qualification such as “synthetic”, “laboratory-grown” or “laboratory-created” should be used. We took note of that advice, although it was not binding on the ASA. We assessed how we considered the average consumer was likely to respond to the ads.
Neither of the ads included an explicit qualification that Linjer’s diamonds were “synthetic”, “laboratory-created” or similar. The ads included the claim “Sustainable Jewelry” or “Sustainable Jewellery”, and “ethically sourced gemstones” in ad (b). We understood that there were concerns about the ethics and sustainability of natural diamonds. However, we did not consider those claims made clear that the diamonds were synthetic, nor was there anything else 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.
We considered that was material information that should have been included upfront, and that the ads were neither limited by time nor space to such an extent that the information could not be provided.
Therefore, because the ads did not make clear that Linjer’s diamonds were synthetic, we concluded that they were misleading.
The ads breached CAP Code (Edition 12) rules 3.1, 3.3 (Misleading advertising) and 3.9 (Qualification).
Action
The ads must not appear again in the form complained of. We told Linjer Ltd not to misleadingly use the term “diamond” to describe their synthetic diamonds in isolation without a clear and prominent qualifier, such as “synthetic” or wording of the same meaning.
