Lab-grown diamonds aren't "manufactured" in the way that word might suggest — they're grown, atom by atom, under the same conditions that create diamonds in the earth, just dramatically faster. There are two methods. Here's how each works, in plain English.
Method 1: HPHT (High Pressure, High Temperature)
HPHT recreates the natural recipe directly. A small diamond "seed" is placed with pure carbon and exposed to extreme pressure (around 1.5 million pounds per square inch) and temperatures above 1,400°C. Under those conditions the carbon melts and crystallizes onto the seed, growing a larger diamond. It's the older of the two methods and mirrors how diamonds form deep underground — just in weeks instead of billions of years.
Method 2: CVD (Chemical Vapor Deposition)
CVD is the newer, increasingly common method. A diamond seed is placed in a sealed chamber filled with carbon-rich gas (typically methane). The gas is heated until carbon atoms separate and settle onto the seed, building the diamond up layer by layer, almost like 3D printing at the atomic level. CVD runs at lower pressure than HPHT and gives growers fine control over the process.
Both produce identical, real diamonds
This is the key point: regardless of method, the result is a real diamond — pure crystallized carbon, the same as a mined stone. The GIA and IGI grade HPHT and CVD diamonds on the same 4Cs scale used for natural diamonds, and the growth method is noted on the report. You can learn more about how lab-grown diamonds are created from the GIA's own explainer.
Does the method matter when you're buying?
For the buyer: not really. What matters is the finished diamond's grades — cut, color, clarity, carat — not whether it was grown by HPHT or CVD. Both methods produce gem-quality stones across the full quality range. Focus on the 4Cs and the grading report, exactly as you would with a natural diamond. We hold every stone, however it was grown, to the same standard — see our accept/reject criteria.
From lab to ring
Once grown, a lab diamond is cut and polished by the same master cutters who shape natural diamonds, graded by an independent lab, and set into a ring. The journey that takes nature one to three billion years takes a few weeks in a lab — and ends with a stone your eye can't tell apart.
Common questions
Is HPHT or CVD better?
Neither is universally "better." Both produce high-quality diamonds across all grades. Judge the finished stone by its 4Cs, not its growth method.
How long does it take to grow a lab diamond?
Typically a few weeks, depending on the size and method — versus the billions of years a natural diamond takes to form.
Ready to see the result? Browse our certified lab-grown diamonds.