Lab-Grown vs Natural Diamonds: The Differences Explained

Both are diamond: carbon with the same crystal structure, hardness, brilliance and fire. A natural diamond formed deep in the earth over millions of years and was mined; a lab-grown diamond is made in a factory in weeks. They look the same, and only a gem laboratory can tell them apart reliably.

There are two methods. HPHT, high pressure and high temperature, recreates the conditions deep in the earth in a press. CVD, chemical vapour deposition, builds diamond layer by layer from a carbon-rich gas onto a thin diamond seed in a vacuum chamber. Both produce real diamond crystals that are then cut and polished.

General Electric made the first reproducible synthetic diamonds in December 1954, a process led by H. Tracy Hall and announced in 1955. Those were tiny industrial stones. GE grew the first gem-quality crystals around 1970, and lab-grown diamonds became common in jewellery much later, as CVD and HPHT production grew.

Not by eye or with a standard diamond tester, which reads both as diamond. Gem laboratories use instruments that detect growth patterns, fluorescence and trace elements. Many lab-grown diamonds are also laser inscribed on the girdle as laboratory-grown, and a GIA report states whether a diamond is natural or laboratory-grown.

Yes. Since 1 October 2025 GIA issues a Laboratory-Grown Diamond Report that describes colourless lab-grown diamonds as premium or standard, instead of giving colour and clarity grades, because almost all fall in a narrow quality range. Coloured lab-grown diamonds receive a separate report. Earlier GIA lab-grown reports remain valid.

Lab-grown diamonds are 10 on the Mohs scale, like natural diamonds, so they cut glass, resist scratching and do not fade, cloud or wear out. Only another diamond can scratch them. Like any diamond, they can chip from a hard knock on a thin edge, and grease on the back dulls their sparkle until cleaned.

Yes. Lab-grown diamonds can be grown or treated in blue, pink, yellow and other colours. Many contain small inclusions from the growth process, such as metallic flux in HPHT stones. Some fluoresce under UV light, and some HPHT stones keep glowing for a moment after the light is switched off, which helps laboratories identify them.

Only if a stone has been replaced or the ring is a modern copy. Gem-quality lab-grown diamonds did not reach jewellery until long after the Art Deco period, so the original diamonds in a Georgian, Victorian, Edwardian or 1920s ring are natural. Old mine and old European cuts are a strong sign of an original natural stone.

Many can. Synthetic opal has been made since the 1970s, synthetic amethyst is grown quartz, and synthetic aquamarine is grown beryl. Tanzanite is usually imitated with glass or other materials. Pearls are not made in laboratories: cultured pearls grow inside molluscs, and anything else is an imitation.

Lab-grown diamonds need no new mining, which avoids its land use and the risk of conflict stones. They do use a lot of energy, so their footprint depends on how the factory is powered. Antique and vintage diamonds are another choice: they reuse stones that were mined long ago and need no new production at all.

A diamond's resale value depends on what buyers will pay second hand. Lab-grown diamonds can be made in any quantity, so buyers value them very differently from natural diamonds, and many specialist buyers value them mainly on the gold or platinum mount. Ask before selling; we give free valuations from photographs.

Look for a laboratory report and check the girdle with a loupe for a laser inscription. If there is neither, a gem laboratory can test the stone. The setting helps too: an antique ring with old cut diamonds and period hallmarks points to natural stones. Send us photographs and any report for a free opinion and valuation.

Yes. Lab-grown diamonds are now also cut in old mine and old European styles to look antique. An old-looking cut therefore does not prove an old diamond: genuine old cuts were shaped by hand, with slightly uneven facets, and a laboratory report states whether any diamond is natural or laboratory-grown.

Neither method is better in itself: both HPHT and CVD produce real diamond, and the quality depends on the individual stone. CVD diamonds are often treated after growth to improve colour. Judge a lab-grown diamond on its cut, colour, clarity and report rather than the growth method.

It is wise to buy any important lab-grown diamond with a report from a recognised laboratory such as GIA or IGI, stating that it is laboratory-grown and describing its quality. Many lab-grown diamonds are also laser inscribed on the girdle. Check that the report number matches the inscription.

Yes. Synthetic sapphire has the same chemistry and hardness as natural sapphire and has been made since the early 1900s by flame fusion, and later by flux and other methods. It is used in jewellery and for watch crystals. A laboratory separates natural from synthetic sapphire.