Lab-grown diamonds are “synthetic”.

Synthetic is something different than a diamond produced in a lab. For example, a synthetic fiber is a different material than natural fiber, one created to simulate natural fiber. This may apply to diamond simulants but lab grown diamond is diamond, not an entirely different material like a diamond simulant.

Using the term “synthetic” to suggest a lab-grown diamond is not an actual diamond is deceptive according to the U.S. Federal Trade Commission.

In other words, while not generally illegal to use this adjective to describe a lab grown diamond, the actual practice of using it is usually inappropriately intended and deceptive. Deceptive marketing is illegal.

Consumers often confuse the term “synthetic diamond” with products such as cubic zirconia—which are not diamonds but completely different materials.

Of course, this confused and derogatory implication is exactly why this terminology is being promoted by the diamond miners and their marketing & industry associations including GIA and CIBJO. Consumers beware!

The diamond miners and their jewelry associations want to exploit and create exactly this confusion between lab grown diamonds and diamond simulants. This is why they are pushing for the use of the qualifier “synthetic”.

The U.S. Federal Trade Commission considered whether “synthetic” was an appropriate way to describe them. They considered evidence that consumers associated “synthetic” with fake or imitation products. Consumer research showed that 56% of consumers understood “synthetic diamond” to mean an imitation or fake. The FTC therefore posited that using the term “synthetic” to suggest a lab-grown diamond was not an actual diamond is deceptive.

The U.S. regulator has also appreciated the fact that synthesis requires multiple elements to be combined, which is plainly not the case with diamond growth.

CIBJO recently decided that “synthetic” should become the sole preferred international term. CIBJO is going further still. Its Diamond Commission has called for exploring “every way possible” to restrict use of the 4Cs to natural diamonds, potentially preventing lab grown diamonds from being described to consumers using the same familiar measures of carat, color, clarity and cut. CIBJO is clearly a pro-mining shop and does not represent the diamond industry at large.

DPC believes CIBJO is acting anti-competitively and harming consumers in the United States and worldwide.

DPC Advises Jewelers to Not Follow CIBJO

We advise jewelers and marketers to stop using “synthetic” for lab-grown diamonds because it confuses consumers about the distinction between diamonds and simulants.

CIBJO is not a government regulator. Its Blue Books are voluntary recommendations. CIBJO itself expressly states: “The application of the Blue Books’ standards is voluntary.”

A jeweler's legal obligations come from the laws and regulations applicable where it does business—not from CIBJO. CIBJO has zero legislative or regulatory authority over jewelers.

U.S. jewelers are subject to U.S. consumer-protection law. The Federal Trade Commission has accepted terminology including “laboratory-grown” and “laboratory-created,” removed “synthetic” from its examples of recommended qualifiers, and has warned that using “synthetic” to imply that a competitor's laboratory-grown diamond is not actually a diamond can be deceptive.

Jewelers should not confuse a CIBJO recommendation with a legal requirement—and should always follow the consumer-protection laws applicable in the market where they operate.

Related news: Diamond Producers Council advises jewelers and retailers to reject CIBJO’s “synthetics” recommendation.

Misleading Marketing by CIBJO and the Diamond Miners

The FTC is the U.S. government agency charged with protecting consumers and competition.

CIBJO, on the other hand, is a jewelry-industry organization whose members and committee participants have substantial commercial interests in natural diamonds.

The FTC asked what terminology could mislead consumers.

CIBJO's Diamond Commission is asking how the terminology and grading system can give natural diamonds a leg up on their lab-grown competitors.

When the two produce directly conflicting recommendations, people should understand whose standard they are being asked to follow.

In 2018, the U.S. Federal Trade Commission conducted an extensive review of the terminology used to describe diamonds. The natural-diamond industry participated. The predecessor of today's Natural Diamond Council/Diamond Collective submitted arguments. International standards, including CIBJO's own Diamond Book, were put before the Commission.

After considering the evidence, the FTC reached several conclusions. First, it removed the word “natural” from the definition of a diamond. Why? Because the old definition dated from an era when mined diamonds were the only diamonds commercially available. Laboratory-grown diamonds now have essentially the same optical, physical and chemical properties as mined diamonds.

The FTC's conclusion could hardly have been clearer: “Thus, they are diamonds.”

Second, the FTC considered whether “synthetic” was an appropriate way to describe them. Consumer research showed that 56% of consumers understood “synthetic diamond” to mean an imitation or fake. Consumers confused the term with products such as cubic zirconia—which are not diamonds. The FTC therefore removed “synthetic” from its examples of recommended qualifying terminology.

And it issued an important warning: Using “synthetic” to imply that a competitor's laboratory-grown diamond is not an actual diamond can be deceptive.

CIBJO has now taken precisely the opposite direction. In 2026, CIBJO decided to recommend “synthetic” as the sole international descriptor and to remove “laboratory-grown” and “laboratory-created” from its preferred Blue Book nomenclature.

The contradiction is striking. The FTC examined consumer evidence showing that “synthetic” can communicate fake diamond.

CIBJO examined the terminology and decided that “synthetic” should become the sole preferred international term.

CIBJO is going further still. Its Diamond Commission has called for exploring “every way possible” to restrict use of the 4Cs to natural diamonds, potentially preventing lab grown diamonds from being described to consumers using the same familiar measures of carat, color, clarity and cut.

This is no longer simply a debate about ensuring that consumers understand where their diamond came from. Everyone should support clear disclosure of origin.

The question is whether an industry organization should use nomenclature to make one category of genuine diamond sound artificial or fake—and then seek to prevent consumers from comparing that product with mined diamonds using the same familiar quality metrics.

Notice to the Jewelers

DPC reserves all rights to pursue legal remedies against jewelers, trade organizations and other market participants that use the term “synthetic” in a manner that misleads one or more consumers into believing that lab grown diamonds are fake, imitation diamonds, or are not diamonds. This applies to representations made in the United States and in other jurisdictions.

Where misleading representations cause consumers to purchase substantially more expensive mined diamonds instead of lab grown diamonds, DPC believes that the resulting consumer price premium may constitute a substantial economic injury and should be considered in assessing available damages, restitution, and other remedies.

DPC is evaluating potential claims, including claims capable of being pursued on behalf of affected classes of consumers, against market participants whose advertising or sales practices materially misrepresent lab grown diamonds.

Compliance with a voluntary CIBJO recommendation does not, by itself, immunize conduct from applicable consumer-protection, competition or advertising law.

Industry terminology cannot be used as a license to mislead consumers.

If you know of a consumer who was misled by a natural diamond marketer describing lab grown diamonds as “synthetics,” please notify us.