What does lab-created mean, and how is it different from simulated?

Quick answerUpdated October 2026

Lab-created (also lab-grown, synthetic, or a maker’s name plus "-created") means the real mineral made in a lab, while simulated (or imitation) means a different material that only looks like the gem. So a lab-created sapphire is , like a mined one, but a simulated sapphire is something else, such as glass, cubic zirconia or lab-grown spinel. The US FTC Jewelry Guides (16 CFR 23.25) say a gem’s name on either kind should come straight after one of these words, and section 23.27 calls it unfair or deceptive to describe a lab-made stone as "real", "genuine" or "natural".

What does lab-created mean?

Lab-created means the stone is the real mineral, made in a factory instead of dug from the ground. GIA describes a synthetic (lab-made) gem as one that shares virtually all the chemical, optical and physical characteristics of its natural counterpart: a lab-created sapphire or ruby is corundum, a lab-created emerald is and a lab-grown diamond is diamond. The US Federal Trade Commission’s Jewelry Guides set the same test in section 23.25(c): "laboratory-grown", "laboratory-created", "[manufacturer name]-created" or "synthetic" should be used with a gem’s name only if the product has essentially the same optical, physical and chemical properties as the stone named. So a lab-created sapphire reads as sapphire on hardness, density and optics, and telling it from a mined stone is a job for a gemmologist or a gem laboratory. The Guides also allow "cultured" for a lab-made gem, but only with a clear disclosure, such as "laboratory-created", that it is not a mined stone.

What does simulated mean, and what is a simulated diamond?

Simulated, or imitation, means a different material that only looks like the gem. GIA explains that the trade calls these materials simulants: they look like another gem and are used in its place, but have a very different chemical composition, crystal structure and optical and physical properties, and they can be natural or man-made. GIA rates glass, plastic, cubic zirconia (CZ) and lab-grown spinel as common simulants, and moissanite as increasingly common. A simulated diamond is anything made to look like a diamond that is not diamond: GIA names CZ, moissanite, YAG (yttrium aluminium garnet), glass, natural zircon and colourless lab-grown spinel. Moissanite sold under its own name is honestly described; it only becomes a problem when it is sold as diamond. A simulant can itself be made in a lab: GIA notes that lab-grown spinel can mimic sapphire, zircon, aquamarine, peridot and other gems, so a blue one sold for sapphire is a simulated sapphire, not a lab-created one.

Which words on a listing mean which?

Words on the listing	What the stone is	What the FTC Jewelry Guides say
Lab-created, lab-grown or [maker]-created sapphire	Sapphire (corundum) made in a lab	Fair only if it has essentially the same optical, physical and chemical properties as sapphire (23.25(c))
Synthetic sapphire	The same thing as lab-created	Grouped with lab-grown and lab-created in 23.25(c), under the same test
Cultured sapphire	A lab-created sapphire	Fair only with a clear disclosure such as "laboratory-created" (Note 2 to 23.25(b))
Simulated or imitation sapphire	A different material that looks like sapphire: glass, CZ, lab-grown spinel or a glass-ceramic	The word should come directly before the gem’s name, as prominent as the name (23.25(b))
Faux sapphire	Lab-made or imitation; the word does not say which	Not an adequate disclosure that the stone is not mined (Note 1 to 23.25(b))
Sapphire, with no qualifier	Should be a mined sapphire	An unqualified gem name is for a mined stone only (23.25(a))
Real, genuine or natural, on a lab-made stone	Still a lab-made stone	Unfair or deceptive (23.27)

Which words on a listing do not tell you what the stone is?

Faux: the FTC says it is not an adequate disclosure on its own, and it does not tell you whether the stone is lab-created or glass. "Ruby colour", "emerald green", "sapphire blue": these describe a colour, not a material. Look for the material elsewhere in the title ("red cubic zirconia"); if no material is named, treat the stone as a simulant. Nano (nano crystal, nanosital) is not a gem mineral. It refers to man-made glass-ceramics: glass in which tiny crystals have been grown. A 2017 study in Ukraine’s Mineralogical Journal found nanoparticles of crystals spread through the glassy matrix of glass-ceramic gem imitations, and GIA’s journal Gems & Gemology (Summer 2026) found that glass-ceramics can be made to look like emerald, sapphire, ruby, peridot and other gems, and are a popular choice for mass-produced fashion jewellery. A nano emerald is not beryl, so it is a simulated emerald, even when a listing calls it lab-created. Grade AAA (or A+, AAAAA): GIA notes that many companies create their own quality descriptions for coloured stones, with AAA, AA and A marking a range within their own goods. The letters are the seller’s ranking, not a laboratory grade, and they say nothing about what the stone is. For the rest of a listing’s wording, see how to read a gem listing.

Is "real", "genuine" or "natural" on a lab stone a red flag?

Yes. Section 23.27 of the FTC Guides calls it unfair or deceptive to describe any jewellery product that is manufactured or produced artificially as "real", "genuine", "natural", "precious" or "semi-precious". A lab sapphire is the same mineral as a mined one, but under the Guides it still should not be called real or natural. A listing that puts "lab-created" and "natural" or "genuine" on the same stone is contradicting itself, so ask the seller which it is, and treat a cheap stone sold as natural without a report from an independent gem laboratory as unproven. Marketplace listings do not always follow the Guides, so every word on a listing is a claim to check, not a guarantee. For how lab and mined stones differ beyond the label, see lab-grown vs natural.

How can you tell which one you have?

You cannot prove at home that a lab-created stone was grown, because it passes the same tests as the mined gem. You can often catch a simulant. Under a jeweller’s loupe, glass usually shows round bubbles or swirl marks, and moulded glass can have rounded facet edges and concave facets; glass also feels warmer to the touch than most of the gems it imitates, according to the International Gem Society. Because a simulant’s optical and physical properties differ from those of the gem it copies, a jeweller’s standard tests, such as and specific gravity, can usually separate it: glass ranges from about 2.30 to 4.50 in specific gravity, and lead raises it, while the glass-ceramics GIA studied read 1.60 to 1.63 on a and were straightforward to separate from the natural stones they imitate with standard testing. Whether a stone is lab-grown or mined is a question for a gem laboratory report.

Frequently Asked Questions

What does simulated diamond mean?

A stone that looks like a diamond but is not one. GIA names cubic zirconia, moissanite, YAG, glass, natural zircon and colourless lab-grown spinel as diamond simulants. The FTC Jewelry Guides define diamond as essentially pure carbon crystallised in the cubic (isometric) system (16 CFR 23.12) and point to 23.25 for imitation diamonds, so a look-alike described with the word diamond should have "simulated" or "imitation" directly before it. A lab-grown diamond is not a simulant: it is diamond, made in a lab.

Is lab-created the same as synthetic?

Yes, in meaning. GIA uses "synthetic" for a lab-made material that shares virtually all the characteristics of the natural mineral, and section 23.25(c) of the FTC Guides groups "synthetic" with "laboratory-grown" and "laboratory-created": each should be used with a gem’s name only if the stone has essentially the same optical, physical and chemical properties as the gem named. The Guides’ list of words to put before the gem’s name gives laboratory-grown, laboratory-created, [manufacturer name]-created or a phrase of like meaning, and does not name "synthetic".

Is a lab-created gem fake?

No. It is the same mineral as the mined gem, with essentially the same hardness and optics. A different material is what makes a stone an imitation, and that is what "simulated" means. Even so, US guidance (16 CFR 23.27) calls it unfair or deceptive to describe a lab-made stone as "real", "genuine" or "natural".

Can a lab-made stone be a simulant?

Yes. Lab-grown spinel is real spinel, but GIA notes it can be made to look like sapphire and other gems. Sold as "simulated sapphire" it is honestly described; sold as "lab-created sapphire" it is not, because it does not have sapphire’s properties.

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