I’ve spent the better part of twenty years peering at diamonds under a loupe, and I’ll admit something upfront: the first time a client asked me about the difference between HPHT and CVD diamonds, I froze for half a second. Not because I didn’t know — but because I knew the real answer was more nuanced than most people expect.
These days, everyone seems to know something about lab created diamonds. Some folks come in convinced they’re all identical; others have heard rumours about colours shifting or strange growth patterns. Every so often someone shows me a TikTok video claiming one method is “bad” or “cheap,” and I can’t help but chuckle. If only gem science were that simple.
So, let’s unravel this in a way that feels real — not overly technical, not dripping with marketing spin. Just the honest truth from someone who handles these stones daily. If you’ve been wondering about HPHT vs CVD, how they differ, and whether one is “better,” you’re in the right place.
Why People Care About HPHT vs CVD in the First Place
A decade ago, maybe even a little more, most customers didn’t ask how their diamond was grown. They just wanted something beautiful, durable, and meaningful. But as interest in sustainability and technology skyrocketed, curiosity about diamond origins exploded right alongside it.
Suddenly, people weren’t only asking about carats and clarity. They wanted to know how the stone came to be: Was it mined from deep rock? Was it grown in a lab? Did it come from a fancy machine or some high-tech plasma chamber?
This shift is part curiosity, part ethical consciousness, and part savvy consumer behaviour. And honestly, it’s refreshing. When customers understand the story behind a gem, they tend to choose more intentionally — and they usually love their diamond more for it.
A Quick (But Not Boring) Breakdown: HPHT vs CVD
Before I jump into what I’ve personally noticed in the workshop, here’s the simplest explanation I’ve ever come up with for the two major growth methods:
HPHT (High Pressure High Temperature)
If you imagine the earth millions of years ago creating diamonds under intense heat and unimaginable pressure, HPHT tries to recreate that. It uses a mechanical press to grow diamond crystals in an environment similar to natural geological forces.
CVD (Chemical Vapour Deposition)
CVD, on the other hand, feels more like something from a sci-fi film. A tiny diamond seed goes into a chamber filled with gas. The gas breaks apart, carbon rains down atom by atom, and slowly — almost hypnotically — a diamond forms layer by layer.
There’s a wonderfully detailed explainer here if you’re the type who loves digging deeper:
HPHT VS CVD.
But let’s keep rolling, because the fascinating part isn’t just how these diamonds grow — it’s how those differences translate into what you actually see on your finger.
What I Actually See With HPHT Diamonds
Let me tell you, the first time you watch an HPHT diamond form under a microscope, it’s wild. The growth structure looks almost like tiny, angular metallic plates — geometric and neat. HPHT diamonds are known for:
1. Strong Temperature Resistance During Growth
Because HPHT uses blisteringly high temperatures, these diamonds often end up with fewer internal stresses. That means they’re generally quite stable.
2. Slight Tint in Early Generations
Old-school HPHT diamonds sometimes had a faint yellow or brown tint. These days? Not so much. Technology improved dramatically. Still, very occasionally I’ll spot tiny metallic inclusions that give their identity away.
3. Excellent for Improving Colour in CVD Diamonds
A lot of people don’t realise this, but HPHT isn’t just a growth method — it’s also used as a treatment to whiten certain CVD stones. When done ethically and disclosed properly, it’s perfectly fine (and quite common in the trade).
What I Notice With CVD Diamonds
I’ll admit something: CVD diamonds hold a soft spot in my heart because watching them grow layer by layer is mesmerizing. They tend to have:
1. Stunning Optical Properties
CVD diamonds often come out incredibly clear, and some have that gorgeous “icy” appearance many of my clients adore.
2. Occasional Growth Striations
If I tilt a CVD stone under the right lighting, I sometimes see faint parallel lines — like subtle fingerprints of the growth process. These don’t affect beauty, but gemologists can spot them.
3. Rare Pinkish or Brownish Hues Pre-Treatment
Some raw CVD stones have a slight warm tone before finishing. Again, modern processes can brighten them significantly.
So… Is HPHT Better? Is CVD Better?
I get asked this at least once a week, and my answer is always the same, though delivered with slightly different wording depending on who’s in front of me:
Neither method is inherently “better.” What matters is the end result.
Think of it this way: two cafés might use completely different brewing methods, but the only thing you care about is whether the coffee tastes amazing.
If a diamond is graded well by a reputable lab, sparkles like it should, and fits your style and values — that’s the winner.
Of course, there are tiny differences worth noting, especially for detail-oriented buyers:
- HPHT diamonds sometimes show metallic inclusions under magnification.
- CVD diamonds can exhibit growth lines or internal graining.
- Both can be colour-enhanced using HPHT post-growth.
- Both can be absolutely stunning when cut and polished well.
- Both are real diamonds — same hardness, same durability, same refractive brilliance.
When I show clients stones side by side, nine out of ten people choose based on look, not method.
Why Lab-Created Diamonds Are Reshaping the Jewellery World
You might not know this, but about a third of my engagement ring customers now choose lab-grown. Twenty years ago? That number was close to zero.
The shift is enormous, and it’s not slowing down.
People love the idea of choosing a diamond that aligns with modern values — ethical sourcing, sustainability, and more transparency. And honestly, who can blame them? Technology has given us an opportunity to enjoy the same beauty without some of the baggage associated with traditional mining.
If you’re exploring style ideas, this guide on lab created diamonds offers some fun inspiration from a fashion-focused angle rather than a jeweller’s perspective.
How I Help People Choose: My Personal Checklist
When someone walks into the workshop clutching a screenshot of two identical diamonds grown using different methods, I guide them through a simple, down-to-earth checklist. No jargon, no pressure — just clarity.
1. Look at the Grading Report First
Is it from IGI, GIA, GCAL?
What do the 4Cs say?
Does one stand out in cut quality?
Cut almost always matters more than HPHT vs CVD.
2. Then Actually Look at the Stone
This sounds obvious, but you’d be surprised how many people buy diamonds sight unseen based on numbers alone. Hold it. Move it. See which one makes your heart jump a little.
3. Consider Long-Term Wear
Both HPHT and CVD diamonds are hard as nails — a 10 on the Mohs scale — so durability isn’t a concern. What I tell clients is to consider personal preference.
Do you prefer the icy look of a CVD stone or the slightly warmer feel HPHT sometimes brings?
4. Think About Price — But Not Too Much
Once upon a time there was a significant price gap. Today? It shifts constantly. I’ve seen HPHT be pricier one month and CVD the next. Let your eyes, not your wallet, lead the way — within reason, of course.
5. Trust Your Instincts
This might sound a little sentimental for a jeweller, but I’ve watched enough people pick engagement rings to know: you usually fall for a diamond the way you fall for a person. Something just clicks.
Some Common Myths I Hear (And The Real Truth)
“CVD diamonds turn brown over time.”
Nope. Not if you’re buying quality. Modern CVD diamonds are stable.
“HPHT diamonds aren’t ethical.”
Factually incorrect. HPHT refers to a growth method — it doesn’t say anything about ethics. Many of the most transparent, eco-focused growers use HPHT.
“One lasts longer than the other.”
They’re both diamonds. They’ll both outlive all of us.
“Jewellers prefer HPHT so they push it.”
We don’t. We prefer diamonds that look incredible and don’t surprise us under the microscope. That’s it.
Where Does the Industry Go From Here?
If you ask me, we’re heading toward a world where almost every couple at least considers lab-grown options — especially younger people. Trends in Australia reflect this too. At trade shows in Melbourne and Sydney, I’ve met more young jewellers who’ve never touched a natural diamond rough in their life but can calibrate a CVD reactor like it’s second nature.
What will be interesting is how technology evolves. Machines that once cost millions are now within reach of mid-sized manufacturers. Colour control is improving. Crystal quality improves every year. We’re even seeing experimental growth shapes — elongated plates, cuboctahedral hybrids, and other bizarre forms that would never appear in nature.
The possibilities feel endless.
Final Thoughts From The Bench
If you’re debating HPHT vs CVD, here’s what I tell clients, friends, even my own family:
Choose the diamond that feels right to you — not the one that comes from the “better” machine.
I know that sounds almost too simple, but after seeing thousands of diamonds in my career, I can promise you this: the magic isn’t in the growth method. It’s in the sparkle, the craftsmanship, the memories attached to it — and the person who picked it with intention.
And honestly? Whether your diamond grew under crushing pressure or in a futuristic plasma chamber, it’s still a little miracle of human ingenuity and natural beauty blended together.