Natural vs lab-grown diamonds: what you're really paying for, and how to choose
"Natural or lab-grown?" is the question I'm asked more than any other. It's a good question, and there's no wrong answer – only the right answer for you. What matters is that you choose knowing exactly what each one is, and what you're paying for.
Both are real diamonds
A lab-grown diamond is not a simulant. Cubic zirconia and moissanite look like diamond; a lab-grown diamond is diamond. Both natural and laboratory-grown diamonds are crystallised carbon with the same chemical, physical and optical properties – the same hardness, the same brilliance and fire, and the same ability to last a lifetime of daily wear.
Lab-grown diamonds are assessed on the same qualities as natural ones – colour, clarity, cut and carat weight – and they can be cut into any shape. Side by side, across a table, you would not be able to tell which is which.
The difference is origin
Natural diamonds formed deep within the earth, under immense heat and pressure, over a span measured in billions of years, and were carried towards the surface by volcanic activity. Each one is a finite piece of geological history.
Lab-grown diamonds are created above ground, usually in a matter of weeks, using one of two methods:
HPHT (high pressure, high temperature) recreates the conditions of the earth's mantle in a press, crystallising carbon onto a small diamond seed.
CVD (chemical vapour deposition) builds a diamond layer by layer from a carbon-rich gas inside a vacuum chamber.
Neither method is "better" in itself. Both can produce beautiful, high-quality stones, and both can produce poor ones. As with natural diamonds, the individual stone and its cutting matter far more than the label.
You can't tell by eye – that's what the report is for
Because they are the same material, natural and lab-grown diamonds can't be separated with a loupe or by eye. Even the basic handheld testers many jewellers use confirm only that a stone is diamond; most can't tell you where it came from. Origin is identified by gemmological laboratories using advanced instruments – spectroscopy and specialised fluorescence imaging, for example – that read the subtle differences in how each diamond grew.
This is why the grading report is so important. Reputable laboratories such as IGI and GIA state clearly whether a diamond is natural or laboratory-grown. Lab-grown stones are typically laser inscribed on the girdle as well, so the origin travels with the stone. GIA, for instance, now issues a distinct assessment for lab-grown diamonds, describing their quality as "Premium" or "Standard" rather than using the colour and clarity scales it developed for natural stones, and inscribes each one "Laboratory-Grown".
Before you buy, check that the report number matches any inscription, and that the weight, measurements and description match the stone in front of you.
Treatments apply to both
Just as with coloured gemstones, treatment is something to ask about, not something to fear. Many CVD diamonds receive post-growth treatment, often a high-temperature process to improve their colour. Natural diamonds can also be treated, for example by laser drilling or fracture filling to improve apparent clarity, or by HPHT processing or irradiation to change colour.
None of this is necessarily a problem, as long as it's disclosed. A reputable laboratory report will note known treatments, and a treated stone should be described and priced accordingly.
What you're really paying for
This is where the two genuinely part ways.
Lab-grown diamonds are produced to demand, so they generally cost considerably less than natural diamonds of a similar size and quality, and their prices have fallen as production has grown. That makes them a compelling way to achieve a larger or higher-grade stone within a given budget. The trade-off is resale: the secondhand market for lab-grown diamonds is limited, and you should assume you would recover little of what you paid.
Natural diamonds are finite, and you're paying for rarity, provenance and a long tradition of value. Natural diamonds have historically retained more of their value on resale than lab-grown, though resale is usually below retail and no diamond should be bought as an investment.
In short, a lab-grown diamond buys you size and quality for your budget; a natural diamond buys you rarity.
Disclosure and the words that matter
Honest terminology protects you. Consumer law in Australia prohibits misleading or deceptive conduct, and the US Federal Trade Commission's Jewelry Guides require that a lab-grown diamond be clearly and prominently described as such – "laboratory-grown", "laboratory-created" or "[manufacturer]-created", for example. The word "diamond" on its own, in most markets, implies a natural stone.
Be wary of vague wording such as "cultured", "eco-diamond" or "real" used without the word "laboratory-grown" alongside it. The origin should be written clearly on the invoice and the report.
How to choose
Start with what the diamond is for, and what matters most to you.
For an engagement ring, both are beautiful, durable choices. Ask yourself whether the meaning of a stone that formed naturally matters to you, or whether you'd rather prioritise size and quality.
If long-term value is important, a natural diamond with a respected laboratory report is the more appropriate choice – though I'd always encourage you to buy a diamond because you love it, not purely as an investment.
If you're working to a budget and want the most visual impact, lab-grown offers more size and quality for your spend.
If ethics guide your decision, look beyond the label. Neither option is automatically the responsible one. The impact of a lab-grown diamond depends on how and where it was produced, including the energy used; for natural diamonds, ask about the source and the chain of custody. Ask for specifics and evidence rather than accepting broad claims.
Questions to ask before you buy
Is this diamond natural or laboratory-grown, and is that stated on the report and the invoice?
Which laboratory issued the report, and can I see the full document?
Has the stone been treated in any way, before or after it was cut?
Is there a laser inscription, and does it match the report?
What is your returns and buyback policy for this stone?
For lab-grown, can you tell me how and where it was produced, and support any sustainability claims?
Where I come in
Whichever path you choose, my role is to make sure you know exactly what you're buying. I source natural and lab-grown diamonds, as well as fine gemstones, read every report carefully, and look at each stone with the same careful eye – so the choice you make is an informed one.
If you're weighing up natural or lab-grown, I'd love to help you think it through. You can make an enquiry here, and I'll reply personally.
Elloise Gee, IGI Graduate Gemologist and founder of Gem House Concierge