Are Lab-Grown Diamonds Real Diamonds? Facts, Myths, and How to Tell
Yes. Lab-grown diamonds are real diamonds by every scientific measure. Same chemical composition, same crystal structure, same hardness, same sparkle. Here is the full explanation.
Diamond vs Simulant: The Science
| Property | Natural Diamond | Lab-Grown Diamond | Moissanite | Cubic Zirconia |
|---|---|---|---|---|
| Chemical formula | C (carbon) | C (carbon) | SiC | ZrO2 |
| Crystal structure | Cubic | Cubic | Hexagonal | Cubic |
| Mohs hardness | 10 | 10 | 9.25 | 8 - 8.5 |
| Refractive index | 2.42 | 2.42 | 2.65 - 2.69 | 2.15 - 2.18 |
| Diamond thermal tester | Pass | Pass | Often pass* | Fail |
| GIA/IGI certified | Yes | Yes | No | No |
| Price per carat (1ct) | $4,000-7,000 | $800-1,500 | $200-600 | $10-50 |
*Moissanite may pass some older thermal testers due to similar thermal conductivity. Multi-tester devices distinguish moissanite from diamond.
The FTC 2018 Ruling
In 2018, the US Federal Trade Commission updated its Jewelry Guides to remove the word "natural" from the definition of diamond. The FTC now defines a diamond as a mineral consisting essentially of pure carbon crystallised in the isometric system. This definition includes lab-grown diamonds. The FTC also issued guidance that calling a lab-grown diamond "synthetic" may be misleading.
How Lab-Grown Diamonds Are Identified
Most lab-grown diamonds sold since around 2020 have a laser inscription on the girdle including the certificate number and LG designation. Visible under 10x magnification. Any jeweller with a loupe can check.
Every certified diamond has a certificate specifying whether it is natural or laboratory-grown. The IGI or GIA certificate clearly states the growth origin. Never buy a diamond without a certificate.
UV fluorescence device that reveals growth patterns. Natural and lab-grown diamonds have different fluorescence patterns. HPHT shows a cross-shaped pattern; CVD shows parallel striations. Very accurate.
Photoluminescence spectroscopy can definitively identify growth method. Requires specialised laboratory equipment and trained gemologists. Used for authentication of high-value stones.
Common Myths Debunked
False. Lab-grown diamonds have identical hardness (10 Mohs) to natural diamonds. They do not scratch, cloud, or degrade. They clean identically and maintain their sparkle indefinitely.
False. Sparkle is determined by cut quality, not origin. An Excellent-cut lab-grown sparkles identically to an Excellent-cut natural of the same specifications.
False. Lab-grown diamonds have identical hardness (10 Mohs) and durability to natural diamonds. They are equally resistant to scratching, chipping, and thermal shock.
False. No gemologist can reliably distinguish lab-grown from natural with the naked eye. Even under a 10x loupe it is not possible without specialised equipment.
False. Each lab-grown diamond is individually grown over 2-4 weeks, individually cut, and individually graded by a certification laboratory. They are not manufactured in batches.
False. Lab-grown diamonds are certified by the same laboratories that grade natural diamonds: GIA, IGI, and GCAL. They are graded on the identical 4C scale.