close-up of a brilliant-cut lab diamond glowing above a CVD reactor with an American flag in the background, symbolizing U.S. lab-grown diamond innovation

How Lab Diamonds Are Made: The Science, Technology, and U.S. Growth Behind Modern Brilliance

September 20, 2026

Quick answer: Lab diamonds are made with HPHT presses, which recreate deep-earth heat and pressure, or CVD reactors, which build diamond from carbon-rich gas layer by layer; the U.S. produced about 1 million carats in 2020, mostly by CVD.

The Evolution of Diamond Creation

Somewhere between a science experiment and a jewelry counter, lab-grown diamonds became the backbone of modern fine jewelry. Using methods with names that sound more like a physics lecture than a love story, High Pressure High Temperature (HPHT) and Chemical Vapor Deposition (CVD), labs across the United States are producing gem-quality diamonds, minus the mining needed to get them. GIA estimates the U.S. produced about 1 million carats of lab-grown diamonds in 2020, mostly by CVD.

HPHT: Basically Recreating the Earth's Core

The HPHT process recreates the heat and pressure in which natural diamonds form, just faster and on purpose. Scientists first grew diamonds in a laboratory in the mid-1950s, with General Electric researchers among the pioneers. HPHT takes a carbon source and a small diamond seed, then heats the growth chamber to 1,300 to 1,600 degrees Celsius at pressures above 870,000 PSI. What comes out the other side is a crystal with essentially the same chemistry as a diamond formed about 100 miles beneath the earth's surface.

CVD: Growing a Diamond Atom by Atom

The CVD process is stranger and, honestly, kind of beautiful. A diamond seed sits in a vacuum chamber filled with methane gas. Microwaves turn that gas into plasma, and carbon atoms slowly stack onto the seed, layer by layer, until you've got a diamond. Today CVD products dominate the lab-grown diamonds submitted to GIA for grading reports, and most CVD stones receive post-growth treatment to improve their color.

U.S. growers, mostly using CVD, have scaled up production, building on technology that GIA notes grew out of the semiconductor industry.

Certification: The Part That Actually Protects You

None of this matters if you can't verify it. That's where GIA and IGI come in. IGI grades lab diamonds with 4Cs assessments: cut, color, clarity, carat. GIA changed its approach on October 1, 2025: it now classifies lab-grown diamonds as Premium or Standard instead of using its natural-diamond color and clarity grades, and laser-inscribes each stone “Laboratory-Grown.”

IGI certified lab-grown diamond ring, grown using CVD technology

Where This Is Actually Happening in the U.S.

New York: Manhattan's Diamond District, a center for cutting, trading and grading.
California: Silicon Valley growers using CVD plasma technology.
Texas: Growing interest in diamond for semiconductor and quantum research.
Florida: Retailers leaning hard into IGI-certified lab diamond rings.

It's Not Just About Rings Anymore

Lab diamonds are quietly powering things you'd never guess: quantum computing, semiconductors, even medical imaging. Lab-grown production is energy intensive, and reported energy use varies widely between producers, so lowering energy use is the next frontier. It's a bigger piece of what people mean now when they talk about the future of jewelry, not just how a piece looks on your hand, but how it actually got there.

Frequently Asked Questions

Are lab diamonds actual diamonds?
They are diamonds, not imitations, and must be described as lab-grown. GIA says a lab-grown diamond has essentially the same chemical, physical and optical properties as a mined one. See our full breakdown of what makes a lab-grown diamond a diamond.

Do lab diamonds hold their value?
Generally no: the resale market for lab diamonds is still small, so resale value is low and uncertain. Buy one for its beauty and price, not as an investment. See our lab-grown diamond price guide for current numbers.

Where can I buy certified lab diamonds in the U.S.?
Start with Future Jewelry or any GIA or IGI certified retailer. Our own lab-grown diamond engagement rings and Future Jewelry Collection are IGI certified from the start.

How long does it actually take to grow one?
GIA says growing diamonds by either method typically requires less than a month for most sizes; very large CVD crystals can take longer.

How does this compare to moissanite?
They're not grown the same way at all, and they're not the same material either. See our full lab-grown diamonds vs. moissanite comparison.

Conclusion

The science behind lab diamonds proves innovation and less mining aren't actually at odds. As American labs keep refining these techniques, lab diamonds are becoming the symbol of a genuinely new era in fine jewelry: technology, craftsmanship, and less mining all pulling in the same direction. That's what we mean by the future of jewelry: diamonds, honestly made.