Lab-Grown Diamond

The single most common question we get is whether these are real diamonds. They are, and the distinction worth drawing is not between real and fake but between diamond and simulant.

A simulant looks like a diamond but is a different material: cubic zirconia, white sapphire, glass. Moissanite is a different material too, silicon carbide, and although it is a beautiful stone in its own right it is not diamond and we never describe it as one. A lab grown diamond is not in that category at all. It is diamond. The International Gem Society classifies it as such, and so do IGI and GIA.

Ronora uses CVD, chemical vapour deposition. It works like this.

1. A thin slice of diamond, called a seed, is placed in a sealed chamber.
2. The chamber is filled with a carbon rich gas, usually methane with hydrogen.
3. Energy breaks the gas apart, freeing carbon atoms.
4. Those atoms settle onto the seed and lock into its existing crystal lattice, layer by layer.
5. Over several weeks the crystal grows upward into a rough diamond.

The rough is then cut and polished by exactly the same craftspeople, on the same wheels, to the same standards as any other rough diamond. Nothing about the finishing is different.

CVD produces large, clean crystals with excellent colour, and it gives close control over the growing conditions. That control is the reason a whole collection can be held to a D-E-F and VVS-VS standard, which would be commercially impossible with mined rough.

Not by looking. Not with a loupe, not with a jeweller's eye, and not with the diamond testers most shops keep on the counter, because those measure thermal conductivity and a lab grown diamond conducts heat exactly like any other diamond.

Laboratories separate them with specialist equipment that reads growth patterns and trace features left by how the crystal formed. It is a laboratory procedure, not a counter test.

There is also nothing hidden about it. Lab grown stones are laser inscribed on the girdle with their report number and their origin, readable under magnification, and the IGI report states it plainly. You will always know what you own, and so will anyone you ever show it to.

A lab grown diamond typically costs substantially less than a mined stone of the same specification. The interesting part is not the saving itself but what you can do with it.

At mined prices, most buyers are forced into a trade. They drop to a G or H colour, or accept an SI clarity, or step down from an Excellent cut, in order to reach a carat weight that feels right. Every one of those is a visible compromise.

Grown, the compromise is unnecessary. That is precisely why Ronora is able to hold Excellent cut, D-E-F colour and VVS-VS clarity across the whole collection rather than on a handful of expensive pieces. It is not generosity. It is what the material makes possible.

Treat any diamond as a purchase rather than an investment. Mined diamonds have a poor resale record too: the gap between retail price and what a dealer will pay you back is large, and always has been. Lab grown prices have also fallen as production has scaled, and may continue to.

If resale value is your main goal, jewellery of any kind is the wrong vehicle. If you want the most beautiful stone you can wear for the next fifty years, that is a different question, and grown is a very good answer to it.

No. It is a 10 on the Mohs scale, the hardest known natural material, and that is a property of the crystal structure rather than of its origin. It will not cloud, yellow or lose its sparkle with age.

What does dull a diamond is a film of soap, lotion and skin oil on the pavilion, and that happens to mined stones just as readily. It comes off with warm water and a soft brush. See our jewellery care guide.

Yes. The same laboratories grade lab grown stones on the same scales, with the report stating the origin. Ronora includes an IGI report with every diamond of one carat or more, and can provide it before you buy rather than after.

Growing a diamond uses energy, and it would be dishonest to pretend otherwise. What it does not do is move roughly 250 tons of earth for a single carat, or carry the water use and land disruption that open pit mining involves.

There is also no sourcing question. A grown stone has a known origin from the first day of its existence. Read the comparison on our natural diamond page, which we wrote so you can weigh it honestly.