Lab-grown and mined diamonds, compared

A lab-grown diamond is the same material as a mined diamond. That is not a marketing position; it is what the material is. The difference between the two is where the carbon crystallised, and almost everything that follows from that is about price rather than about the stone.

What is the same

Chemically, physically and optically, there is nothing to separate them. Both are carbon in the same cubic crystal lattice, atom for atom. Both measure 10 on the Mohs scale, the hardest material known. Both refract light the same way, which is why both sparkle the way they do.

A jeweller cannot tell them apart by eye, and neither can a loupe. That is not a failing of the tools — there is no visual difference to find.

What is different

Time and place. A mined diamond formed in the earth's mantle over a period measured in the hundreds of millions of years and was carried up by volcanic activity. A lab-grown diamond is made in a chamber over a period measured in weeks.

DLV's lab-grown diamonds are CVD — chemical vapour deposition. A thin seed crystal is placed in a chamber, a carbon-rich gas is introduced, and the gas is broken down so that carbon atoms settle onto the seed and continue its crystal structure. The stone grows layer by layer, in the same lattice, and is then cut and polished exactly as a mined diamond is.

What a laboratory can tell

Specialist equipment can distinguish them, and reputable laboratories do. The growth process leaves traces — patterns in how the crystal formed, particular fluorescence under specific wavelengths — that identification instruments read. Larger lab-grown diamonds are often laser-inscribed and certified as lab-grown by a grading laboratory.

That distinction matters and we state it everywhere. A stone sold without saying whether it is a lab-grown diamond or a mined diamond has been sold dishonestly, whichever it turns out to be.

What changes is the price

The same size, colour and clarity costs substantially less in a lab-grown diamond. What the saving is used for is the interesting part: the same budget reaches a larger stone, a better cut, a cleaner grade, or all three.

What does not change

• The hardness. It will not scratch or cloud with age.
• The grading. The same 4Cs, the same scales.
• The care. It is cleaned and looked after exactly as a mined diamond is.
• The setting. The gold, the workmanship and the hallmarking are the same.

Which should you choose

That is a question about what the stone is for rather than about the stone.

Somebody buying a stone as an heirloom with a story about the earth attached will want a mined diamond, and should. Somebody buying a stone to wear, who would rather have two carats than one for the same money, should look seriously at lab-grown diamonds.

Both are the same material. Only one of them requires a compromise on size to fit most budgets.