We are going to give you an unusual answer to this one: nobody can tell you a reliable percentage, and you should be wary of anyone who does.

You will find confident-sounding figures all over the internet. Most trace back to a single analyst estimate, a press release, or another blog quoting a blog. Very few come with a stated methodology, and almost none say what they are actually measuring.

Rather than add another invented number to the pile, here is why the question is so hard to answer, what can honestly be said about the direction of travel, and what you probably wanted to know underneath the question.

Why there is no single percentage

“What percent of diamonds are lab-grown” sounds like one question. It is at least six, and they give wildly different answers.

Percent of what, exactly?

• By number of stones? Industrial diamond production dwarfs gem production, and the overwhelming majority of industrial diamond is synthetic — used in drill bits, saw blades and abrasives. Counted this way, most diamonds made on earth today are lab-grown, and the figure tells you nothing about jewellery.
• By carat weight of gem-quality stones? A different number entirely.
• By retail value? Different again, and much lower — because lab-grown stones cost less, the same number of stones represents a smaller share of money spent.
• By number of engagement rings sold? Different again, and this is usually the highest figure.

Where, exactly?

Adoption varies enormously between markets. The United States, India, China and the United Kingdom are all at different points, and a global average conceals more than it reveals. A figure quoted for US engagement rings tells a UK buyer very little.

Measured by whom?

There is no compulsory register of diamond sales. Estimates are assembled by industry analysts and consultancies from surveys, customs data, manufacturer reporting and retail sampling. Reputable work exists — the annual global diamond reports published by consultancies, and the analysis of specialist trade analysts — but these are estimates with genuine error margins, published for the trade, and often behind a paywall.

Add to that the fact that both sides of this market have an interest in the number. Mining companies benefit from a low figure. Lab-grown producers benefit from a high one. Press releases are not measurements.

What can honestly be said

Direction, not decimals. These statements are safe:

• The lab-grown share of diamond jewellery has grown substantially over the last decade, from a niche to a mainstream option.
• Growth has been fastest in engagement rings, where price sensitivity and stone size matter most.
• Lab-grown prices have fallen considerably as production capacity and technology have improved, which is why the share by value lags well behind the share by unit.
• All the major grading laboratories now run full lab-grown grading services, which they would not do for a marginal product.
• Most large jewellery retailers now stock both, which was not true a decade ago.

That is as far as honest reporting goes without citing a specific, dated, methodologically transparent source — and any such source would be out of date within a year in a market moving this fast.

The question underneath the question

In our experience people rarely want the percentage for its own sake. They want to know one of these things instead.

“Will people think it is odd?”

No. Lab-grown diamonds are common enough now that most people either own one, know someone who does, or have seen them in a high street window. The conversation has shifted from “what is that?” to “which did you choose?”

“Am I making a strange choice?”

You are making a mainstream one. There are good reasons to prefer either lab-grown or natural, and both are legitimate. What matters is that the stone is certificated and that you know exactly what you bought. Our comparison of lab-grown versus natural diamonds lays out both cases without spin.

“Will it hold its value if lots of people have one?”

No, but not for that reason. Lab-grown diamonds have poor resale value, and so — less famously — does most natural diamond jewellery once you compare retail with what a trader will pay. Buy either to wear, not as an asset. We go into this properly in how much are lab diamonds worth.

“Is this a fad that will disappear?”

The stone in your ring is diamond either way — carbon, hardness 10, unchanged in a hundred years. Whatever happens to market share, the object on your finger does not become less of a diamond.

How to read a statistic you see quoted

If you do come across a figure and want to judge it, four quick tests:

1. Does it say by unit, by carat or by value? If not, it is not a usable number.
2. Does it name a market and a year? “Globally, at some point” is not data.
3. Does it name a source with a method? A consultancy report with a stated methodology beats an infographic.
4. Who benefits from the number? Check whether the publisher sells one type of diamond.

This is the same scepticism worth applying to environmental claims on both sides of this industry, which are similarly full of confident figures with no measurement behind them.

Frequently asked questions

Are most engagement rings sold today lab-grown?

In some markets the lab-grown share of engagement rings has become very substantial; in others it remains smaller. We are not going to quote a figure we cannot stand behind. What is clear is that it is no longer unusual anywhere.

Are lab-grown diamonds becoming more popular in the UK?

Yes, clearly — measured by how many retailers stock them, how many are certificated, and how routine the question has become in our own enquiries. We can describe that trend honestly without inventing a percentage for it.

Does a bigger market share make lab-grown cheaper?

Prices have fallen, but the main driver is production capacity and improving growth technology rather than demand. More supply, at lower cost, means lower prices.

Will lab-grown diamonds replace natural ones?

Unlikely, and it is not really the right frame. They increasingly serve different buyers with different priorities. Some people want the geological age and rarity; others want the size, clarity and documented origin. Both markets can exist.

Why do you not quote statistics on your blog?

Because we would have to make them up or repeat someone else’s unverified figure. We would rather tell you what we know and be plain about what we do not.

Judge the stones, not the statistics

What actually matters when you buy is far more concrete than market share: is the stone certificated, is the cut good, is it eye-clean, is the setting well made, and can you verify what you have been told.

Every centre stone we set is an untreated lab-grown diamond with a free IGI certificate, laser-inscribed so you can check the report number yourself. Everything is hand-made in solid gold or platinum in North Harrow, London, with free insured UK delivery and 30-day returns.

Have a look at the Solitaire Round Cut Engagement Ring at £657 or the Hidden Halo Oval Cut Engagement Ring at £1,021 (correct at the time of writing), or browse the full engagement ring collection.