Are Lab-Grown Diamonds Real? 7 Questions UK Buyers Ask Before Saying Yes

Yes, lab-grown diamonds are real diamonds. They have the same chemical composition (pure crystallised carbon), the same hardness (10 on the Mohs scale) and the same sparkle as diamonds pulled out of the ground. The only differences are where they come from, and what they cost. A 1.0ct lab-grown solitaire in 18k gold starts at £1,795 at Not Mined; a comparable mined diamond ring in the UK typically costs £6,000 or more. Below, we answer the seven questions UK buyers ask most before choosing one for an engagement ring.

In this article

• Are lab-grown diamonds real diamonds?
• How are lab-grown diamonds made?
• Can a jeweller tell the difference?
• Why are lab-grown diamonds so much cheaper?
• Do lab-grown diamonds last?
• Are lab-grown diamonds more ethical?
• Do lab-grown diamonds hold their value?
• FAQ

1. Are lab-grown diamonds real diamonds?

Chemically, physically and optically, a lab-grown diamond is identical to a mined one. Both are pure carbon arranged in the same crystal structure. Gemological institutes including the GIA and IGI grade lab-grown diamonds using the same 4Cs (cut, colour, clarity, carat) they use for mined stones, and since 2018 the US Federal Trade Commission has defined both as simply "diamond". The one thing that differs is origin, which is why every certified lab-grown diamond is laser-inscribed on its girdle so its provenance is never in doubt.

	Lab-grown diamond	Mined diamond
Composition	Pure crystallised carbon	Pure crystallised carbon
Hardness	10 (Mohs)	10 (Mohs)
Graded by GIA/IGI	Yes, same 4Cs	Yes, same 4Cs
Time to form	2 to 8 weeks	1 to 3 billion years
Typical UK price, 1.0ct ring	£1,500 to £2,500	£6,000+
Mining involved	None	Yes

2. How are lab-grown diamonds made?

Two methods dominate. CVD (Chemical Vapour Deposition) places a thin diamond seed in a chamber filled with carbon-rich gas; the gas is heated until carbon atoms rain onto the seed and crystallise, layer by layer. HPHT (High Pressure High Temperature) recreates the conditions of the earth's mantle, pressing carbon around a seed at around 1,500°C. Both produce a rough diamond in 2 to 8 weeks, which is then cut and polished by exactly the same craftspeople, with exactly the same tools, as a mined stone.

3. Can a jeweller tell the difference between lab-grown and natural diamonds?

Not by eye, and not with a loupe. A trained gemologist with standard equipment cannot separate a lab-grown diamond from a mined one, because there is no visual difference to find. Telling them apart requires specialist spectroscopy machines that read the stone's growth pattern. In practice, origin is identified the simple way: certified lab-grown diamonds carry a microscopic laser inscription (usually "LG" plus the certificate number) on the girdle, invisible to the naked eye.

4. Why are lab-grown diamonds so much cheaper?

Price, not quality. A mined diamond passes through exploration, heavy mining machinery, rough-stone auctions and a long chain of middlemen before it reaches a UK jeweller. A lab-grown diamond goes from grower to cutter to setter. Removing the mine and the middlemen removes 60 to 80 per cent of the cost, which is why our 18k gold, 1.0ct Classic Oval Cut Solitaire starts at £1,795 rather than £6,000. You are not buying a lesser diamond. You are skipping the queue of people who each took a margin.

5. Do lab-grown diamonds last as long as mined diamonds?

Yes. Hardness is a property of the crystal, not of its birthplace. At 10 on the Mohs scale, a lab-grown diamond is exactly as scratch-resistant, chip-resistant and heirloom-proof as a mined one. It will not fade, cloud or "wear out". Set in 18k gold, it is an everyday ring for a lifetime, and the stone will outlast the band, the box and all of us.

6. Are lab-grown diamonds more ethical?

On the biggest question, origin, the answer is simple: a lab-grown diamond cannot be a conflict diamond, because it was never mined. There is no displaced community, no open-pit mine and no murky rough-stone supply chain; you know exactly where the stone came from. The fair caveat is energy: growing diamonds takes electricity, and growers vary in how clean theirs is. It is a real consideration, but a transparent one, which is more than can be said for tracing a mined stone back through five owners to a pit.

7. Do lab-grown diamonds hold their value?

Here is the honest answer most retailers skirt around: no, lab-grown diamonds do not currently hold resale value well, because growing technology keeps getting cheaper. But context matters. Mined diamonds are not the investment they are marketed as either; most resell at a steep discount to their retail price the moment they leave the shop. If you buy a £8,000 mined ring and it resells at 40 per cent, you have lost £4,800. Buy a £1,795 lab-grown ring and even if it resold at zero, you are still thousands of pounds better off, on a stone that is physically identical. An engagement ring is not a stock. It is worn, not traded, and the sensible question is not "what will it resell for" but "what did I pay for the same sparkle".

Frequently asked questions

Is moissanite a lab-grown diamond?

No. Moissanite is a different gemstone entirely (silicon carbide), with different hardness (9.25 Mohs) and a more rainbow-like sparkle. A lab-grown diamond is a diamond; moissanite is a diamond alternative.

Will a lab-grown diamond pass a diamond tester?

Yes. Standard handheld testers measure thermal conductivity, and because a lab-grown diamond is a diamond, it passes exactly as a mined stone does.

Are lab-grown diamonds certified?

Yes. Reputable lab-grown diamonds come with an independent grading report from institutes such as IGI or GIA, covering the same 4Cs as mined stones, and the certificate number is laser-inscribed on the stone's girdle. Ask us about certification →

How much is a 1ct lab-grown diamond engagement ring in the UK?

Expect £1,500 to £2,500 for a certified 1.0ct lab-grown diamond in an 18k gold setting. At Not Mined, classic 1.0ct solitaires start at £1,795, with 1.5ct options available across every cut. Browse the engagement ring collection or book a free consultation to talk through options for your budget.

Can you tell a lab-grown diamond apart once it is on your finger?

No. Nobody, including a jeweller, can tell by looking. The only way to know is to read the laser inscription under magnification or test the stone with specialist lab equipment.