Lab grown or natural? Our honest answer after fifty years in the trade.
People expect us to be snobby about lab grown diamonds. We are not. What we are is honest. And the honest answer is more interesting than you might think.
By Simon Johnson, Co-Founder and Gemmologist, Marmalade Fine Jewellery
[NOTE: Byline establishes authority immediately. This is expert opinion, not a marketing page.]
First, let us clear something up.
Synthetic gemstones are not new. Jewellers have been working with them for well over a century. The flame fusion process for creating synthetic rubies and sapphires was developed in the 1880s. Hydrothermal synthetic emeralds have existed for nearly as long. Cultured pearls, in which human intervention triggers the pearl-forming process, have been part of the jewellery trade since the early twentieth century.
The principle has always been the same. A synthetic gemstone must be chemically, physically and optically identical to its natural counterpart. If it is not, it is an imitation, not a synthetic. Lab grown diamonds pass that test completely. Without specialist gemmological equipment, it is impossible to tell a lab grown diamond from a natural one. They are the same thing. The difference is entirely in their origin.
Where they come from.
A natural diamond was formed at least a billion years ago, deep within the earth, under conditions of extreme heat and pressure that no laboratory can fully replicate at scale. It was carried toward the surface by volcanic activity, mined from the ground, cut, polished, and eventually found its way to a jeweller's window. That journey took at least a billion years.
A lab grown diamond was produced in a massive factory, almost certainly in Asia, using one of two methods: High Pressure High Temperature, which mimics the conditions of natural formation, or Chemical Vapour Deposition, which builds the diamond atom by atom from a carbon-rich gas. The process takes between a few days and a few weeks.
One stone took a billion years and a volcano. The other took a factory and a fortnight. Both are diamonds. Only one has a story.
What has happened to the price.
This is where the conversation gets interesting, and where we think people deserve a straight answer.
When lab grown diamonds first came to market at scale, they were positioned as ethical luxury at a modest discount to natural stones. That positioning has not held. As manufacturing has become more efficient and production has scaled dramatically, the price of lab grown diamonds has fallen by around eighty percent since 2020. A one-carat lab grown diamond that might have cost three thousand pounds five years ago can now be purchased for under a thousand.
Natural diamond prices have also softened, but nothing like as dramatically. The gap between the two has widened every year.
The numbers today
A one-carat natural diamond of good quality retails at roughly four to five times the price of an equivalent lab grown stone. Lab grown diamond prices have fallen around eighty percent since 2020 and continue to decline as production capacity grows. Natural diamond prices have fallen roughly twenty-five percent in the same period.
The practical consequence of this is significant. If your priority is size, a lab grown diamond will give you a considerably larger stone for the same money. A couple who might have considered a one-carat natural diamond can now buy a two or even three-carat lab grown stone at a similar price point.
What you do not get with a lab grown diamond.
Two things. Rarity and resale value.
Natural diamonds are rare. They took over a billion years to form, they exist in finite quantities, and the cost of extracting them from the earth is substantial. Rarity is the foundation of value in the luxury goods world. Lab grown diamonds are not rare. They are manufactured in factories that are running twenty-four hours a day, producing stones that are chemically identical to natural diamonds but available in essentially unlimited quantities. The price will continue to fall.
Consumer research published in 2024 found that while the vast majority of buyers acknowledge that lab grown and natural diamonds are visually identical, only around one in four attributed emotional value to a lab grown stone, compared to nearly nine in ten for natural diamonds. That emotional gap matters when a piece of jewellery is passed down, insured, valued, or sold.
We value a great many lab grown diamond pieces at Marmalade. Our honest advice to clients is always the same: a lab grown diamond has very limited resale or insurance replacement value compared to its purchase price. That is not a reason not to buy one. It is simply something you should know.
What about ethics and sustainability?
Lab grown diamonds are often marketed on the basis that they are more ethical and sustainable than mined stones. We think this deserves a more nuanced look.
The diamond mining industry has changed substantially over the past two decades. The Kimberley Process, for all its imperfections, has significantly reduced the trade in conflict diamonds. Responsible sourcing standards have improved. Many mining operations support local communities and economies in ways that factory production does not.
Lab grown diamond production, meanwhile, is energy intensive. The HPHT and CVD processes require significant electricity, and the majority of production takes place in countries where that electricity is generated from fossil fuels. The sustainability case is not as straightforward as the marketing suggests.
We source our natural diamonds through established, traceable channels and can tell you the provenance of every stone we sell. We think that matters more than a broad claim about laboratory origin.
So which should you choose?
Choose a lab grown diamond if
Size is your priority and you want the largest, most visually impressive stone your budget will allow. You are buying a piece for its beauty and wearability rather than as a long-term investment or family heirloom. You are entirely comfortable with the fact that its value will not hold in the way a natural diamond's would.
Choose a natural diamond if
You want a stone with genuine rarity, a provenance measured in geological time, and a value that is grounded in something finite. You are buying a piece that you hope will be worn, cherished and perhaps passed on for generations. The story of where it came from matters to you.
We sell both. We will never tell you one is better than the other in absolute terms. We will always tell you the truth about what you are buying, and help you make the choice that is right for you.
We have been having this conversation for fifty years. Come and have it with us.
