Lab-grown diamonds, what they really are

The words still give people pause. Here is what such a stone is made of, how it is identified, what our report says, and why the house chose it.

What is it made of?

The same carbon, in the same crystal structure, with the same hardness and the same refractive index as a mined diamond. That is what a gemmological laboratory measures, and it is why an ordinary examination is not enough to tell them apart. What changes is how it formed: it was created in a growth laboratory, over a few weeks, instead of forming in the earth over geological time.

It is not an imitation. Cubic zirconia, often wrongly called zircon, is another material, far softer, and zircon is a distinct natural stone. A laboratory-grown diamond is diamond.

How is such a stone grown?

By two routes, both known for a long time. The first reproduces the conditions of the earth's mantle: very high pressure and very high temperature, around a diamond seed. The second grows the stone layer by layer, depositing carbon from a gas inside a low-pressure chamber. Either way it takes a few weeks: the diamond crystal grows from carbon around a seed.

Can you see the difference?

Not with the naked eye, and not reliably with a loupe. Some laboratory-grown stones leave clues a trained gemmologist may notice under magnification: particular growth patterns, metallic inclusions, the absence of the mineral inclusions typical of a mined stone. But those clues are neither constant nor conclusive.

A sure identification calls for specialised instruments: fluorescence readings, spectroscopy, dedicated equipment used by laboratories. It is a laboratory examination, not a glance across a counter. In practice, what settles the matter is the report supplied with the stone.

What does our report say?

Our diamonds are certified by IGI, from 0.5 carat. The report grades colour, clarity, cut and carat, and states that the stone is laboratory-grown. We write it too, on every page and every piece.

Our reference quality for white stones: colour D, clarity VS1 or better.

How does it differ from a mined diamond?

In three ways: how it forms, where it comes from, and price. How it forms, as we have said. Origin: a laboratory-grown diamond comes from a production facility, which provides a starting point for tracing its origin. Laboratory growth alone does not guarantee full traceability: this also requires documentation from the supply chain. Price: at comparable quality, it puts sizes within reach that mining reserved for the few.

What it does not change: the stone itself, its light and how it holds over time.

What is it worth on resale?

The question deserves a frank answer. A ring is not an investment. The second-hand market generally returns a fraction of the price paid, and that holds for pieces set with mined stones too, whose resale value depends on the stone, the moment and the buyer. The price of laboratory-grown stones has also fallen in recent years, as production has settled. What you keep is therefore not a resale value: it is a piece, its metal, the work that made it. For the same budget, a laboratory-grown stone gives you more stone, and more ring.

What do we call them, exactly?

The house says laboratory-grown, everywhere and without exception. Rather than flattering adjectives, we describe the composition and the properties of the stone: it says exactly the same thing, and it can be checked. In everyday use you will also hear "lab-grown" and, in French, "diamant de synthèse": it is the same stone.

And the coloured stones?

Our sapphires, rubies and emeralds are laboratory-grown, and we always say so. They come from Chatham, the American house that has been growing emeralds since the 1930s.

Why did the house choose laboratory-grown stones?

Out of consistency. ORIGINE PARIS was born of a conviction: ecology is not an option. Our gold is recycled, and setting mined stones in it would have been contradictory. A laboratory-grown stone does not ask for a mine to be opened.

We do not claim for that reason that it is without impact: growing it takes energy, and a great deal of it. What we say is simpler and can be checked: the diamond itself is grown in a laboratory rather than extracted from the earth, and its production belongs to an identified site.

So how do you choose your stone?

By looking. Shape first, which makes the character of the ring; size next, which makes its presence; quality last, which the report describes. The best way to decide is to try: in the configurator the price of the ring follows each of your choices, immediately. Our price guide sets out what makes it up: What makes the price of a bespoke ring.

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