Over the last six months, I’ve been getting more and more detailed questions about lab diamonds (lab-grown diamonds). I’ll try to make this topic as clear and simple as possible: what they are, how they’re made, the difference between HPHT and CVD, and when a lab-grown diamond is the best choice for you.
Quick Summary
A lab-grown diamond is a real diamond – it has the same chemical composition and optical properties as a mined diamond; the difference is the origin.
Lab-grown diamonds are mainly produced in two ways: HPHT and CVD.
It’s not a rule that HPHT is always better than CVD or vice versa – both methods can produce very high-quality stones; differences show up more in typical “fingerprints” (tone, inclusions, structure).
Lab-grown diamonds are often more affordable and for many people a more ethical choice, but it’s important to understand that market value and resale behavior can be different compared to natural stones.
What Is a Lab-Grown Diamond?
A lab-grown diamond is a diamond created in a controlled environment using technological processes that mimic natural diamond formation. In nature, diamonds form under extreme pressure and heat over very long periods of time, while in a lab a crystal can grow in weeks or months (depending on the method and the desired result).
Important: a lab-grown diamond is not cubic zirconia or glass—it is a diamond, with the same physical and optical properties as a natural diamond.
How Are Lab Diamonds Made?
1) HPHT (High Pressure High Temperature)
The HPHT method uses very high pressure and temperature to simulate the conditions under which diamonds form in nature. In a reactor, the diamond is grown larger on a “seed” crystal.
What to know (practically):
HPHT is used both to grow diamonds and sometimes (in certain cases) to improve color.
Some HPHT stones can show specific growth features or micro-traces related to metallic catalysts (which labs can identify).
2) CVD (Chemical Vapor Deposition)
In CVD, the diamond grows from a gas mixture (a carbon-containing gas). In an activated environment, carbon deposits layer by layer onto a diamond seed and forms a crystal. Generally, it requires less pressure/heat than HPHT.
What to know (practically):
CVD stones can sometimes show tones (e.g., slightly grayish/brownish) or growth-related structures, which can be improved through treatment and careful selection.
HPHT vs CVD: Which One Is Better?
It’s important to correct a common misconception here: there is no universal rule that HPHT is always higher quality and CVD is always lower quality—or the other way around.
Today, both methods produce very high-quality diamonds, and the final result depends on:
the producer’s standards,
how the crystal grew,
any post-growth processes,
and (most importantly) the specific stone’s 4Cs + certificate.
Practical advice: don’t choose based on the HPHT/CVD label—choose based on the specific stone (certificate + video + measurements + 4Cs).
Why Do People Choose Lab-Grown Diamonds?
1) A bigger or higher-quality stone for the same budget
With the same budget, you can often get:
a higher carat weight,
better color/clarity,
or both at once.
2) Ethical and more transparent production
For many people, this choice is about reducing the risks associated with mining (including conflict issues and working conditions). If this topic matters to you, it pairs well with reading your “blood diamonds” article (and supply-chain topics in general).
3) Look and sparkle
With a good cut, a lab-grown diamond sparkles the same as a natural diamond—because the optical properties are the same.
What Are the Downsides or Question Marks?
1) “Romance” and “mystique”
For some people, the natural diamond story—“from the earth, millions of years old”—matters emotionally. You can’t talk someone out of that with technical arguments. It depends on taste and personal values.
2) Resale market and value retention
Lab-grown diamond pricing has been more dynamic, and resale behavior differs from natural diamonds (which also aren’t a “quick investment”). If long-term value retention matters to you beyond emotional value, it’s worth factoring this in consciously.
3) Energy use and environmental footprint
Lab production requires energy. If environmental impact is your main argument, what becomes important is where and how the diamond was produced (energy mix, producer standards). (It’s reasonable to ask the seller directly.)
How to Make a Confident Choice (A Simple Decision Framework)
Choose a lab-grown diamond if:
you want maximum value for your budget,
you want a larger stone or higher quality,
you prefer a modern and often more transparent option.
Choose a natural diamond if:
tradition and the “nature” narrative are important to you,
you want the classic choice people have historically selected most often.
And in both cases:
don’t decide based only on “carat,”
Cut is king,
always ask for a certificate (GIA/IGI, etc.) and actually view the stone (photo/video).
Summary
A lab-grown diamond is a real diamond—the difference is origin. HPHT and CVD are the two main production methods, and today both can produce very beautiful, high-quality stones. In the end, the right choice is the one that fits your:
budget,
values,
and the meaning you want your engagement ring to carry.