Are lab grown diamonds real?

People ask this question for three different reasons, and each one has its own answer. Is it legally a diamond? Is it physically a diamond? Is it worth what a diamond is worth? The first two are a clean yes. The third is where buyers get burned.

Answer 1: the legal one

In the United States, the Federal Trade Commission's Jewelry Guides decide what a seller can call a diamond. Until 2018 the definition began with "a natural mineral." In its 2018 revision the FTC dropped the word natural. A diamond is now "a mineral consisting essentially of pure carbon crystallized in the isometric system." The Commission's reasoning was blunt: it is no longer accurate to define diamonds as natural when products with essentially the same optical, physical and chemical properties can be made.

What the FTC still requires is disclosure. A lab made diamond has to be clearly qualified:

So a seller who calls a lab stone simply "a diamond" breaks the guides, and a seller who calls it "fake" is wrong. Both happen.

Answer 2: the physical one

GIA states that laboratory grown diamonds have essentially the same chemical, physical and optical properties as natural diamonds. The American Gem Society says the same in its lab grown FAQ. They are made two ways:

• HPHT (high pressure, high temperature). A press squeezes carbon around a seed crystal at conditions similar to those deep in the Earth.
• CVD (chemical vapor deposition). Carbon from a hydrocarbon gas settles onto a seed plate layer by layer inside a vacuum chamber.

Here is how a lab grown stone compares on the properties that home tests and tester pens read:

Can anyone tell them apart?

Not by eye and not at home. GIA says that in some cases a trained gemologist with standard equipment can spot growth features, and in other cases it takes advanced instruments that read strain patterns, trace elements, fluorescence and phosphorescence. Growth conditions leave markers that even reveal which method was used, but you need a lab to read them. Every home test and every handheld thermal pen will call a lab grown diamond a diamond, because it is one.

One quirk worth knowing: diamonds that contain boron (type IIb, the kind that is naturally blue) conduct electricity. Some HPHT lab stones contain boron, and an electrical tester can read them as moissanite. If a stone sold as lab grown "tests as moissanite," that is the first thing a jeweler will check. More on that in how diamond testers work.

Answer 3: the money one

This is where "real" stops being enough. A lab grown diamond is real, but it is not scarce, and the market prices it that way.

• Retail price is far lower than a natural stone of the same grade, and it has kept falling as production grows.
• Resale is weak. Many jewelers and buyback programs will not purchase lab grown stones at all, or offer a small fraction of what you paid. Assume you are buying something to wear, not an asset.
• Grading reports matter more. A report from GIA or IGI states the origin. Our page on diamond certificates explains which labs are trusted.

For a side by side on price, durability and resale, see lab grown vs natural diamond. If you are trying to price a stone you already own, start with what is my diamond worth.

Myths that keep circulating

How to know which one you have

Work through this list in order. Stop as soon as you get a firm answer.

• Paperwork. The receipt or grading report should say laboratory grown if it is. Reports from major labs state origin on the first line.
• Girdle inscription. Many lab grown stones carry a laser inscription on the girdle that says LG or laboratory grown plus a report number. You need a 10x loupe and good light to read it.
• Jeweler screening. Many jewelers own a screening device that flags stones for further testing. A flag does not mean lab grown, it means send it to a lab.
• Lab report. The definitive answer, and the only one worth relying on for an insurance appraisal or a sale.

How lab grown diamonds are graded

Because lab grown stones are diamond, the major labs grade them with the same tools they use for mined stones and print the origin clearly on the report. That matters when you buy, and it matters even more if a stone ever changes hands.

If you are buying secondhand, the report is the stone's passport. A seller who cannot produce one for a stone described as natural is asking you to trust them on the single fact that sets the price. Our guide to GIA vs IGI vs EGL explains why some reports carry more weight than others.

Our take

Stop asking whether lab grown diamonds are real. They are. Ask whether the price matches what you are getting and whether the seller disclosed the origin. If you want a diamond to wear and you care about size and grade per dollar, lab grown is a reasonable buy. If you want something that holds value, it is the wrong purchase. And if you are weighing it against moissanite, we compare the two directly in moissanite vs lab diamond.

Worth being clear: everything here, and the app itself, is an educational reference. At-home tests narrow things down, they do not certify a stone. Before you buy, sell or insure anything of real value, get it looked at by a certified gemologist or an independent appraiser.