How are Lab-Grown Diamonds Made? CVD vs. HPHT Explained

Lab-grown diamonds are created by replicating the heat and pressure conditions that form natural diamonds. They’re real diamonds, chemically and visually identical to mined ones, grown in weeks instead of billions of years.

There are multiple ways to grow a diamond, but the two most common are:

1. CVD (Chemical Vapor Deposition)
2. HPHT (High Pressure High Temperature).

Each method mimics nature’s process in a high-tech lab, and yields stunning diamonds with the same sparkle, hardness, and brilliance as those from deep in the Earth. We’ll also touch on less common techniques like Detonation Synthesis and Ultrasound Cavitation so you can understand exactly how the science works, and which methods matter most when you’re ring shopping.

Quick Overview: How Lab Diamonds Are Made

Lab-grown diamonds start with one thing: carbon. But how that carbon is transformed into a stunning, sparkle-loaded diamond depends on the technology behind it. Here’s a snapshot of the most common and emerging methods used to create lab-grown diamonds today:

High Pressure High Temperature (HPHT)

HPHT mimics the extreme conditions of the Earth’s mantle, using over 1,500°C of heat and 1.5 million PSI of pressure, to turn carbon into crystal. A small diamond seed is placed in carbon and subjected to intense pressure inside a mechanical press. The carbon melts and forms around the seed, creating a larger diamond. Metal catalysts like iron or nickel help speed up this process. HPHT diamonds often grow faster and emerge in near-final form but may contain metallic inclusions.

Chemical Vapor Deposition (CVD)

CVD starts with a diamond seed placed in a vacuum chamber. Methane gas and hydrogen are pumped in and heated to form plasma, allowing carbon atoms to rain down and build the diamond layer by layer. Most diamonds take 2–4 weeks to grow, and CVD offers better control over clarity and color. However, CVD stones can show brown undertones and often undergo post-growth treatment (like HPHT) to enhance their appearance.

Detonation Synthesis

This method uses explosives to create nano-diamonds, tiny crystals that aren’t suitable for jewelry but have industrial uses. You won’t find these in any engagement ring.

Ultrasound Cavitation

A futuristic lab technique where ultrasonic waves create high-energy bubbles in liquid carbon, breaking atomic bonds and encouraging diamond formation. This method is still in experimental stages and not commercially used for jewelry-grade stones.

Emerging Methods

As demand grows, so does innovation. Some labs now use solar or renewable energy to power diamond growth, while others experiment with trace element doping (like nitrogen or boron) during growth to control color more precisely. Hybrid approaches, starting with CVD and refining with HPHT, are also gaining traction to improve clarity and minimize visible flaws.

Inside the Lab: CVD vs. HPHT

How CVD Diamonds Are Grown

CVD, or Chemical Vapor Deposition, is a modern, precise way to grow diamonds from scratch. It starts with a thin diamond “seed” placed in a vacuum chamber. Then, gases like methane and hydrogen are pumped in and heated until they break down into plasma. From there, carbon atoms settle on the seed and build upward, layer by layer, over several weeks.

This method gives labs tight control over the diamond’s structure and clarity. But here’s the tradeoff: many CVD diamonds emerge with a slight brown or grayish hue due to impurities or trace nitrogen in the growth chamber. To correct that, many stones undergo a second HPHT treatment after growth to whiten the color and improve appearance.

And there’s one more hidden perk to CVD: labs can intentionally add elements like nitrogen or boron during growth to create natural-looking colored diamonds in yellow, blue, and more. It’s not just chemistry, it’s craftsmanship.

How HPHT Diamonds Are Grown

HPHT, High Pressure High Temperature, is the original lab-grown diamond method, and it’s still one of the most powerful. By replicating the same extreme conditions found deep within the Earth’s mantle (think 1,500°C heat and pressures over a million PSI), carbon is transformed into a solid diamond crystal. The process often uses a metal catalyst like nickel or iron to help initiate growth.

HPHT diamonds tend to grow faster than CVD stones and, in many cases, come out of the press needing little or no enhancement. That means no extra post-processing, just cut, polish, and sparkle. However, HPHT isn’t without quirks. These diamonds are more prone to metallic inclusions from the catalysts used in growth, which can sometimes be spotted under magnification.

Can You Tell Them Apart?

Let’s settle one of the biggest questions upfront: Can you tell a lab-grown diamond from a mined one just by looking?

The answer is no. Not with your eyes. Not with a loupe. Not even with most jeweler’s tools.

CVD and HPHT diamonds are chemically, physically, and optically identical to mined diamonds. They have the same crystal structure, the same fire and brilliance, the same hardness. Unless someone brings it into a gemological lab and runs it through advanced spectroscopic analysis, like photoluminescence or infrared testing, there’s no visual giveaway.

So if you’re worried, “Will people know my diamond is lab-made?”, the honest answer is: only if you tell them.

That said, transparency matters. At Mikado Diamonds, we make sure every lab-grown diamond we offer is clearly certified and laser-inscribed for full traceability. Not because you need to prove anything to anyone, but because you deserve to know exactly what you’re buying, and why it’s worth it.

Are Lab-Grown Diamonds Really Worth It?

Featured Product -> 3.55 ct. E/VVS2 Asscher Cut Lab-Grown Diamond Engagement Ring | Mikado Diamonds

Lab-grown diamonds are not “fake.” They’re not knockoffs. And they’re definitely not moissanite.

Lab-grown diamonds are real diamonds, same atomic structure, same sparkle, same hardness. In fact, they rate a 10 on the Mohs scale, just like mined diamonds. The only difference is origin: one is formed in the Earth over billions of years; the other is formed in a lab over a few weeks. That’s it.

Still hearing “Aren’t they just like moissanite?” Let’s break that down. Moissanite is a diamond simulant, it looks similar, but it’s made from silicon carbide, not carbon. It’s softer, it refracts light differently, and to trained eyes, it doesn’t hold a candle to a diamond. A moissanite will never be a diamond, and no reputable jeweler will try to blur that line.

The Science Is Legit (and Kind of Awesome)

What’s happening in these labs isn’t some automated, button-press miracle, it’s precision science. Lab-grown diamonds are built atom by atom, layer by layer, in a process that mirrors Earth’s forces with incredible accuracy. This isn’t easy, cheap, or plug-and-play, it’s controlled brilliance.

And while AI tools are popping up everywhere, here’s a truth we stand by at Mikado: AI can’t pick a diamond, and it sure can’t grow one. Creating a quality diamond takes human oversight, experience, and craftsmanship. No algorithm can judge nuance like light performance, inclusion placement, or cut proportion.

Durability, Resale & Real Concerns

Let’s talk about durability. Lab-grown diamonds are every bit as hard and scratch-resistant as mined diamonds. Both hit a perfect 10 on the Mohs scale. Both are built to last lifetimes. So if you’re worried a lab diamond might chip or wear down over time, it won’t. Not unless you’re swinging a hammer at it (please don’t).

Neither lab-grown nor mined diamonds are great for resale, unless the stone is rare, antique, or carries historic provenance. Most people won’t get back what they paid, regardless of origin. That’s not a lab-grown problem. That’s a diamond market reality.

The real value in a diamond isn’t its resale, it’s its meaning. It’s the moment you propose. It’s the sparkle your partner sees every day. If you’re buying a diamond for love, not as a stock investment, then no, you’re not throwing money away. You’re putting it where it matters most.

But What About Energy Use?

Growing diamonds in a lab still takes energy. Especially with HPHT, where machines generate the kind of pressure and heat found 100 miles beneath the Earth’s surface. That’s not exactly low-power.

So while lab-grown diamonds avoid the environmental destruction of mining, they’re not “energy-free.” The difference is in how that energy is sourced, and how upfront the producer is about it.

Some labs now run entirely on solar or renewable energy, dramatically reducing the carbon footprint. Others are still catching up. And unfortunately, not every seller discloses where their stones come from or how they were grown.

Ethical + Emotional ROI

For a long time, diamonds were sold as status symbols, proof of wealth, tradition, or prestige. But more couples today are choosing something different: rings that reflect their values, not just their budget.

Custom engagement rings made with lab-grown diamonds are personal. You’re creating something new. Something that says, we chose this together, for us.

Is a Lab Diamond Right for You?

Ask Yourself These Questions:

You’ve seen the science. You understand the ethics. But here’s the real question, is a lab-grown diamond the right fit for you?

Ask yourself:

• Do I want size and sparkle without a mined diamond’s markup?Lab-grown diamonds now cost 70–90% less than their mined counterparts. That means you can size up dramatically, or save big, without compromising on quality.
• Am I buying for beauty or resale value? If your goal is long-term investment or auction-block resale, a rare mined stone might be the path. But if you’re buying for brilliance, symbolism, and lasting beauty, lab-grown delivers in every way that counts.
• Do I care about ethics, customization, and personal service? Choosing a lab diamond lets you align your purchase with your values. And when you design it with Mikado Diamonds, you’re getting more than a stone, you’re getting one-on-one expert guidance, visual previews, and pressure-free support.

This isn’t about compromise. It’s about choosing a ring that reflects what actually matters to you.

Still Unsure? Here's What to Watch For:

If you're still on the fence, you're not alone. The lab diamond space can be confusing, especially when every online listing sounds the same. So here’s what I always tell clients to keep an eye on:

• Watch for unwanted blue nuances or undertones: Some HPHT diamonds can show a faint blue tint. It’s not always bad, but it should be disclosed, and visible in natural lighting, not just lab specs.
• Look out for growth lines or internal striations: These are more common in CVD diamonds. They don’t affect durability, but they can affect appearance. A good jeweler will flag these for you before you ever see them in person.
• Be cautious with overly treated stones: Some diamonds go through multiple post-growth treatments to improve color or clarity. That’s fine, if it’s disclosed. If it’s hidden, that’s a red flag.
• And above all, don’t buy based on specs alone: Two diamonds with identical 4Cs can look completely different in real life. Always ask for videos, high-resolution photos, or a virtual consultation.

We’re obsessive about this stuff. We inspect every diamond ourselves before it ever makes it to our clients. Because the only surprise you should feel when opening that ring box is joy.

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Book a Free Consultation

Still have questions about CVD vs. HPHT? Wondering if you should go 3 carats or scale back for a higher color grade? Want to see what your dream ring could actually look like?

We’ve got you.

Every consultation is one-on-one, pressure-free, and tailored to you. We’ll walk you through carat-size trade-offs, diamond shapes, clarity considerations, and more, with visuals, side-by-sides, and expert advice that actually makes sense.

Whether you’re just starting out or almost ready to buy, we’re here to make this process feel simple, transparent, and exciting.

Explore Our Collection

Not all online diamond listings are created equal. Some are AI-generated placeholders with generic specs and no real accountability. That’s not how we do things.

With us, you can browse real diamonds with real specs, curated and hand-reviewed by experts, not machines. Want to see how that 3.5-carat oval actually sparkles? We’ll send you videos. Want a side-by-side of radiant vs. emerald cuts? We’ll show you.

And if you ever get stuck or overwhelmed, you can talk to a real human, someone who’s walked hundreds of couples through this exact process.

Because choosing a diamond should feel personal, not robotic. And sparkle shouldn’t be left to chance.

Still Have Questions?

Buying a diamond, especially a lab-grown one, can feel like stepping into a world full of noise. Conflicting info. Overhyped specs. Too many tabs open.

So if you're still unsure, overwhelmed, or just want someone to talk to who actually listens, reach out.

At Mikado Diamonds, there's no pressure, no gimmicks. Just honest advice from people who’ve been where you are. We’ll help you make sense of the science, the sparkle, and everything in between, so you can move forward with confidence, clarity, and a ring you’ll love forever.

Consult with a jewelry expert

Frequently Asked Questions

Q: Is a lab-grown diamond resellable or upgradable later?

A: Most diamonds, lab or mined, don’t hold resale value unless they’re antique or rare. But yes, you can upgrade with some jewelers. At Mikado Diamonds, we focus on helping you get it right the first time, not banking on trade-ins.

Q: Do HPHT diamonds last longer than CVD diamonds?

A: Not in any meaningful way. Both are 10/10 on the Mohs scale and equally durable for daily wear. The difference lies more in appearance (metallic inclusions in HPHT, brown undertones in CVD) than strength.

Q: Are post-growth treatments like HPHT “cheating”?

A: Not at all. Post-treatments are standard in both lab-grown and mined diamonds. What matters is transparency, knowing whether a diamond has been treated and how that affects its look and value.

Q: How do lab conditions mimic natural geological processes?

A: HPHT replicates the high pressure and heat of the Earth’s mantle. CVD mimics the chemical conditions that allow carbon to crystallize in low-pressure environments. Both recreate nature, just faster and with more control.