Every supplier has a favorite technology. Usually it's the one they happen to own. We source both, so this comparison is actually honest.
If you've been sourcing lab-grown diamonds for more than five minutes, you've heard the question: "CVD or HPHT?" Most suppliers will pitch you whichever technology their factory uses. We don't own a factory — we represent you, the buyer. So here's the unvarnished comparison.
HPHT replicates how nature makes diamonds — extreme heat (1300-1600°C) and pressure (5-6 GPa) applied to a carbon source with a metal catalyst. Think of it as a geological process accelerated from millions of years to a few days. China dominates HPHT production, with the Henan cluster alone accounting for the majority of global output.
Key players: 力量钻石 (Liliang Diamond, SZ:301071), 惠丰钻石,黄河旋风 (Huanghe Whirlwind, SH:600172)
CVD grows diamonds atom by atom in a vacuum chamber. Methane gas is energized into plasma, releasing carbon atoms that deposit onto a diamond seed plate. It's slower (2-4 weeks per batch) but produces diamonds with exceptional purity — no metal catalyst means no metallic inclusions.
Key players: 中南钻石 (Zhongnan Diamond, subsidiary of China Ordnance Industries), 黄河旋风 (dual-technology), international players like WD Lab Grown Diamonds
| Dimension | HPHT | CVD |
|---|---|---|
| Color | D-F grades more common (30-40% of output). Color tends to be uniform and stable. | G-H dominant (70-80% of output). May show brownish undertones requiring post-growth treatment. |
| Clarity | VS1-VS2 typical. Possible metallic inclusions from catalyst. Internal structure can be complex. | VVS1-VVS2 more common (40-50% of output). No metal contamination. Cleaner internal structure. |
| Type | Typically Type Ib or IIa (depending on nitrogen content) | Almost always Type IIa — the purest diamond type, same as the Koh-i-Noor and Cullinan |
| Size Range | 0.3-3ct commercial range well-established. Large stones (3ct+) increasingly viable. | 0.3-2ct mainstream. Larger stones require longer growth cycles, raising cost. |
| Production Speed | Days per batch. Faster turnaround for volume orders. | 2-4 weeks per batch. Slower but more controllable. |
| Cost Structure | High equipment investment (六面顶压机), lower per-carat cost at scale. | Lower equipment cost, higher per-carat cost for large stones. |
| Internal Stress | Lower internal stress. More stable during setting and wear. | Can have higher internal stress. Occasionally problematic during setting. |
| Fluorescence | Often strong blue fluorescence under UV. Some buyers see this as a plus. | Typically none to faint. More predictable appearance. |
This is where most guides end with "both are great!" Not helpful. Here's how we advise our procurement clients, based on what they actually sell:
Your customer wants a 1-1.5ct round brilliant that looks white and sparkles. They don't care about diamond types.
HPHT gives you reliable color at a competitive per-carat price. At 1-1.5ct, the slight clarity advantage of CVD is irrelevant — VS1 is already eye-clean. Save the CVD premium for your budget.
Your customer wants 2ct+, will verify the certificate, and cares about the "Type IIa" designation.
At this tier, Type IIa purity and VVS clarity become selling points you can articulate. CVD produces these more reliably. The premium is justified because your customer will pay for the story.
You need 0.3ct accent stones and 1ct center stones in consistent quality.
CVD's clarity advantage shines in smaller stones where inclusions are proportionally more visible. HPHT gives you the color consistency for center stones.
Your buyers prioritize high color grades. They may ask specifically about technology.
HPHT's superior color yield (30-40% D-F vs CVD's 5-10%) makes it the natural choice. Chinese buyers are increasingly educated about HPHT and may prefer it as the "domestic" technology.
One more thing to watch: GIA and IGI grade HPHT and CVD differently. IGI tends to be more generous across both technologies, but the gap is wider for HPHT stones — particularly on color. If you're sourcing HPHT with IGI certificates for a GIA-preferred market, factor in a potential one-grade downgrade.
There is no "better" technology — only the better technology for your specific market. We've seen jewelers waste thousands buying CVD for markets that don't care, and others lose deals because their HPHT stones didn't carry the Type IIa cachet their high-end clients expected.
Our job as your procurement advocate is to match the technology to the market, not to push one over the other. Tell us about your market — we'll tell you which tech wins. →