NDC Prevails in U.K. Case Over Lab-Grown Diamond Advertising

Editor’s Note: This story was updated post-publication to include comment from Skydiamond.

London—The U.K.’s Advertising Standards Authority (ASA) announced it has upheld the Natural Diamond Council’s complaint against retailer Skydiamond for misleading marketing and advertisement of lab-grown diamonds.

The online fine jewelry retailer uses a patented process to create diamonds from atmospheric carbon dioxide and rainwater using renewable energy from solar and wind power, its website states.

The NDC’s complaint alleged that it was misleading for Skydiamond to use the terms “Skydiamonds,” “diamonds,” and “diamonds made entirely from the sky” in ads it featured in early 2023 in press, on its Instagram, and on its website.

It also called into question the use of the words “real diamond” in a section of the retailer’s FAQ page that answered the question “Are Skydiamonds real diamonds?” with “Each Skydiamond is a perfectly formed real diamond.”

In its ruling, the ASA, which is the U.K. equivalent of the Federal Trade Commission (FTC), sided with NDC, stating that the ads did not make it clear that the diamonds were lab grown. 

It also said the above terms were misleading, and the ads breached the U.K. Code of Non-Broadcast Advertising, Sales Promotion and Direct Marketing rules 3.1 and 3.3, with regards to misleading advertising, and 3.9, with regards to qualification.  

The code states, “marketing communications must not mislead the consumer by omitting material information. They must not mislead by hiding material information or presenting it in an unclear, unintelligible, ambiguous, or untimely manner.” 

All of Skydiamond’s ads included clear gemstones and references to diamonds, the ruling said, and it considered consumers would understand “diamond” in insolation to mean a naturally occurring mineral of crystallized carbon. 

While some consumers would be aware that diamonds could be manufactured in a lab, ASA said, many would not. 

ASA directed Skydiamond not to use the above terms to describe their lab-grown diamonds without a clear and prominent qualifier, such as “synthetic,” “laboratory-grown” or “laboratory-created,” or another way of conveying the same meaning to consumers in a direct and obvious manner.  

It also told the retailer the ads must not appear again in the form complained about, and to not use the claim “real diamonds” to describe lab-grown diamonds. 

Skydiamond said it plans to appeal the ruling, calling it “a mistake.” 

“Our website and all of our marketing, indeed our very name, make clear that our diamonds come from the sky, we make them or mine them from the sky," said Dale Vince, founder of Skydiamond.

"We make that very clear. Nobody could possibly think they are conventional stones ripped from the bowels of the earth at enormous environmental cost, and nobody actually has. This complaint is not based on actual confusion on the part of customer; it comes from the trade body for diamond mining companies, [and] it is an attempt to use the ASA for anti-competitive purposes and it utterly baseless."

The NDC, which filed in March 2023, based its complaint on the Diamond Terminology Guideline, a reference document that, as of 2020, is assured and recognized by Trading Standards in the U.K. market.

The U.K.’s National Association of Jewellers, along with leading industry organizations, have endorsed the guideline, which is built on the ISO 18323 Standard (“Jewellery – Consumer confidence in the diamond industry”) and the CIBJO Diamond Blue Book.

The FTC has its own rules on diamond terminology, but it is not recognized for diamonds sold outside the United States.

The Diamond Terminology Guideline states that all documents, websites, and other means of communication intended to sell, buy, and promote natural diamonds, lab-grown diamonds, gemstones, lab reports, and natural and lab-grown diamond jewelry must use “synthetic,” “laboratory-grown” or “laboratory-created” when referring to lab-grown diamonds, a directive the ASA references in its ruling.

In one section of its lengthy response to NDC’s complaint, Skydiamond called the guideline a tool that “should not be, and did not profess to be, the only basis for defining the origin of a diamond or for determining definitively whether diamond ads were misleading to an average consumer.” 

Skydiamond also argued that of the 23 steps in its “novel and innovative” production process, only the CVD step was shared with conventional lab-grown diamond production processes, and commercialization of its process post-dated the introduction of the Diamond Terminology Guideline, so it was not considered for inclusion. 

The ASA acknowledged in its ruling that the guideline had been updated in 2023, but there were no major changes to the 2020 version. 

And, although it agrees Skydiamond’s production process differs from other diamond growers, ASA said the diamonds were lab grown nonetheless and consumers needed to know that before making a transactional decision. 

 
The NDC’s complaint to the ASA regarding misleading terminology in advertisements for lab-grown diamonds initially included three other U.K. retailers—Stephen Webster, Lark & Berry, and Idyl. 

According to NDC, ASA dropped its case against Stephen Webster but did note that its ruling in the Skydiamond case also applies to Stephen Webster’s marketing and communications. 

A spokesperson for Stephen Webster said the company had no comment on the ruling. 

The ASA investigated ads from the other two retailers and considered them to be in breach of code—Lark & Berry for the use of “cultured diamond” and “diamond” without a qualifier when referring to synthetic diamonds, and Idyl for the use of the terms “diamonds,” “diamond sparkle,” “fine diamond jewelry,” “sustainable diamonds,” and “Diamonds of the Future” in the same context.

Lark & Berry agreed to amend the ads with qualifiers such as “synthetic,” “laboratory-grown,” and “laboratory-created.”

Idyl also agreed to amend their advertisements that targeted U.K. consumers. 

Both rulings have been published as informally resolved on ASA’s website.