How lab-grown diamonds are made: CVD and HPHT

CVD, HPHT: the two methods that grow real diamonds in a few weeks. Understanding how a lab-grown diamond is made, simply.

Doing in weeks what the Earth does in millions of years

A diamond, natural or lab-grown, is always born the same way: carbon atoms organising into a crystal lattice under extreme conditions. The Earth achieves this more than a hundred kilometres down, over geological time. The laboratory achieves it in a few weeks, with two main technologies.

HPHT: reproducing the Earth's mantle

The HPHT method (High Pressure, High Temperature) is the older one. A diamond seed is placed in a press with a carbon source, heated to around 1,500 °C under colossal pressure — the very conditions of the Earth's mantle. The carbon dissolves, migrates to the seed and crystallises layer after layer. It is the historic method, particularly suited to very white stones.

CVD: growing the crystal atom by atom

The CVD method (Chemical Vapor Deposition) also starts from a diamond seed, this time placed in a low-pressure chamber filled with a carbon-rich gas. A plasma breaks the gas down, and the carbon atoms deposit onto the seed, atomic layer after atomic layer. The crystal literally grows under control, with remarkable purity.

Then, the same journey as every diamond

Once the rough stone is obtained, it follows exactly the same path as a mined diamond: it is studied, cleaved, cut and polished by the same craftsmen, using the same techniques and the same ideal proportions. The cut — the factor that decides brilliance — obeys the same rules, and the stones are graded by the same 4C criteria.

It is that stone, cut and certified, that MICKAEL STONE sets on 14-karat gold in every one of its creations.

Frequently asked questions

CVD or HPHT: which is better?

Both produce real gem-quality diamonds. What matters to you are the 4Cs of the finished stone, not its growth method.

How long does it take to grow a diamond?

From a few weeks to about two months, depending on the target size and the method.

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