Is a lab-grown diamond a real diamond? What the FTC Jewelry Guides say

A lab-grown diamond is a diamond in the material sense, and the FTC's Jewelry Guides treat it that way with one condition: the seller has to say where it came from. Section 23.12 defines a diamond by what it is, a mineral of essentially pure carbon, and a later section limits words such as natural and genuine for artificially produced goods. Everything below is read from the eCFR text current as of October 22, 2026.

What the FTC says a diamond is

The definition in 16 CFR 23.12(a) is chemistry and physics. "A diamond is a mineral consisting essentially of pure carbon crystallized in the isometric system. It is found in many colors. Its hardness is 10; its specific gravity is approximately 3.52; and it has a refractive index of 2.42." The paragraph does not use the word natural and does not mention a mine.

The FTC revised the Jewelry Guides in 2018. Its July 24, 2018 release listed "the definition of 'diamond'" among the sections revised, along with the treatment of "cultured" diamonds. We opened that release and it does not quote an official on the change, so we are not describing what the old wording said.

Facet count also matters. Section 23.12(b) calls the unqualified word diamond deceptive for an object "which, though meeting such requirements, has not been symmetrically fashioned with at least seventeen (17) polished facets." Rough stones can still be called "rough diamond," and a stone with fewer facets can carry the word if the seller discloses the facet count and shape, as with a "rose diamond."

The disclosure rule for lab-grown stones

The Guides allow "cultured" for laboratory-created diamonds with the same optical, physical and chemical properties as mined ones, but only "if the term is qualified by a clear and conspicuous disclosure." The examples are "laboratory-created," "laboratory-grown," or "[manufacturer name]-created," or a phrase of like meaning "conveying that the product is not a mined stone."

For gemstones generally, section 23.25 requires the word ruby, sapphire and the like, when used for a laboratory-grown stone, to be "immediately preceded with equal conspicuousness" by a word such as laboratory-grown. The note adds that "faux" is not an adequate disclosure. Section 23.25(c) also says the words laboratory-grown or synthetic may be used with a natural stone's name only if the product has "essentially the same optical, physical, and chemical properties as the stone named."

The catch-all is section 23.27: it is unfair or deceptive to use "real," "genuine," "natural," "precious," "semi-precious," or similar terms to describe an industry product that is manufactured or produced artificially. A listing for a lab-grown stone that calls itself a genuine natural diamond is the kind of claim the section covers.

How the stones are made and told apart

Wikipedia's entry on lab-grown diamonds describes two production routes. High pressure, high temperature uses large presses that can weigh hundreds of tons to produce 5 GPa (730,000 psi) at 1,500 degrees Celsius (2,730 degrees Fahrenheit). Chemical vapor deposition creates a carbon plasma over a substrate where atoms deposit to form diamond. The entry says gem-quality stones can be "chemically, physically, and optically identical to naturally occurring ones."

Identical in material does not mean undetectable. The same entry says synthetic diamonds can be distinguished by spectroscopy in infrared, ultraviolet or X-ray wavelengths, and that De Beers' DiamondView uses ultraviolet fluorescence to detect trace impurities such as nitrogen or nickel. It also says GIA, IGI and GSI laser-inscribe the girdle of lab-grown stones they certify "with their report number and an indication that the diamond is lab-grown," visible at 10x magnification, and that GIA dropped the word synthetic from its lab-grown reports in July 2019 after the revised FTC guidelines.

What the price and market numbers say

Wikipedia reports that by early 2025 lab-grown diamond prices had fallen "by 74% since 2020," and that in 2023 synthetic diamonds were 17 percent of the diamond jewelry market. Treat both as secondary estimates from that entry, not figures we verified at a primary source. The same entry says CNN Business reported in April 2022 that a one-carat synthetic round was up to 73 percent cheaper than a natural one with the same features.

What the numbers show without our help is the direction: a stone that was scarce when the technology started is now a product category with its own price ladder. That is why the labeling rule has teeth. A buyer comparing two rings is comparing two very different supply stories.

How to read a listing

• Look for the full phrase. Laboratory-grown, laboratory-created or a maker's name should sit next to the word diamond, at the same prominence.
• Ask for the grading report. The reports from the labs named above identify lab-grown stones, and the girdle inscription is how a jeweler can check.
• Treat "faux," "simulated" and "imitation" as different things. A stone that does not meet the definition above is not a diamond. A lab-grown diamond does meet it.
• Do not rely on "natural" or "genuine" wording alone. Section 23.27 bars those words for artificially produced products.
• Remember the Guides are guidance. Section 23.0(d) says they "do not confer any rights on any person and do not operate to bind the FTC or the public," but that the Commission "may take action under the FTC Act if a marketer or other industry member makes a claim inconsistent with the guides."

Our take

Call a lab-grown diamond what the FTC does: a diamond with a disclosure attached. If you want a mined stone for its origin, pay for the paperwork that proves it. If you want the stone for how it looks, a lab-grown one is the same material under the Guides' own definition, and the label should say so in plain words. We would skip any listing that leans on "real" versus "fake," because the FTC's text turns on disclosure and composition, not on authenticity theater. For more on how the Guides handle other materials, see our explainer on gold plated, gold filled and vermeil.