Quick Answer
Lab-grown diamonds are made two ways. HPHT (High-Pressure High-Temperature) squeezes a carbon source around a diamond seed under extreme pressure and heat, similar to conditions deep in the earth. CVD (Chemical Vapor Deposition) turns carbon-rich gas into plasma inside a vacuum chamber, letting carbon atoms settle onto a thin diamond seed layer by layer. Both start from a real diamond seed and grow a genuine diamond in weeks rather than the billions of years natural formation takes.
What Is HPHT (High-Pressure High-Temperature) Diamond Growing?
HPHT growing recreates the pressure and heat found deep in the earth's mantle, using specialized presses to compress a carbon source around a diamond seed at extreme temperature. Over roughly one to two weeks, carbon atoms bond onto the seed in the same crystal lattice as a mined diamond, growing a real diamond from the inside out.
- Presses apply thousands of atmospheres of pressure alongside temperatures over roughly 1,300°C
- A small diamond seed sits at the center and the crystal grows outward from it
- The process compresses, on a much shorter timeline, the pressure-heat conditions that form diamonds naturally underground
- HPHT equipment is also used to treat the color of some mined and lab-grown stones after growth
What Is CVD (Chemical Vapor Deposition) Diamond Growing?
CVD growing places a thin diamond seed plate inside a sealed chamber filled with carbon-rich gas, usually a mix of methane and hydrogen, then energizes the gas into plasma. Freed carbon atoms settle onto the seed as pure crystal, building the diamond layer by layer over several weeks until the rough stone reaches a workable size.
- The seed is a thin slice of diamond, often cut from a previously grown stone
- Microwave energy turns the carbon-rich gas into plasma, breaking the gas molecules apart
- Freed carbon atoms settle onto the seed one atomic layer at a time
- CVD chambers typically run at lower pressure than HPHT presses and need less specialized equipment
HPHT vs CVD: Which Method Makes the "Better" Diamond?
Neither method makes a "better" diamond than the other — HPHT and CVD both produce a genuine diamond with the same hardness, brilliance, and crystal structure as a mined stone. The real difference is process, not quality: HPHT compresses carbon under extreme pressure, while CVD deposits it from a gas at lower pressure. What actually varies from stone to stone is cut, color, and clarity, not which method grew it.
| Factor | HPHT | CVD |
|---|---|---|
| Growth conditions | Extreme pressure plus high heat, similar to deep-earth conditions | Carbon-rich gas turned to plasma in a vacuum chamber |
| Typical timeline | About one to two weeks per stone | About two to four weeks per stone |
| Common role today | Growing diamonds and color-treating existing stones | Growing diamonds, widely used for larger production runs |
| Result | A real diamond, graded on cut, color, clarity, carat | A real diamond, graded on cut, color, clarity, carat |
How Long Does It Take to Grow a Lab-Grown Diamond?
Most lab-grown diamonds finish growing in about two to four weeks, depending on target size and method, compared with the roughly one to three billion years mined diamonds are estimated to take underground. Cutting, polishing, and grading add more time after growth, but the crystal-growing stage itself is measured in weeks, not millennia.
- Smaller stones generally finish faster than larger ones, since more carbon has to bond for bigger rough
- After growing, rough stones still need cutting and polishing before they're ring-ready
- Growers can run multiple chambers at once, which is part of why lab-grown diamond supply has scaled up quickly
Where Does Moissanite Fit In If You Want That Look Today?
Moissanite is not a lab-grown diamond — it is a separate mineral, silicon carbide, a diamond simulant that is also created in a lab but forms a different crystal than carbon-based diamond. MYNSU currently sells moissanite set in 925 sterling silver, not lab-grown diamonds, as a lower-cost way to get a diamond-like look right now.
- Moissanite is silicon carbide — a different mineral from diamond, not a lower grade of it
- MYNSU's current catalog is moissanite in 925 sterling silver, not lab-grown or mined diamond
- If a lab-grown diamond ring is the long-term goal, a moissanite piece can be a lower-cost placeholder with a similar sparkle in the meantime
A round solitaire is the classic starting point if you're comparing silhouettes before you decide what to buy:
A six-prong setting is a familiar shape if you're used to browsing diamond rings and want the same silhouette:
For a flatter, everyday-friendly profile, a band-set style skips the raised prongs entirely:
Our lab-grown diamond vs moissanite comparison and our guide to what makes a lab-grown diamond a real diamond both cover this decision in more depth.
Frequently Asked Questions
Is a lab-grown diamond a real diamond?
Yes. Since the FTC updated its Jewelry Guides in 2018, a diamond is defined by its chemistry and crystal structure, not by whether it formed underground or in a lab. A lab-grown diamond has the same carbon composition, hardness, and optical properties as a mined one — a real diamond, not a simulant like moissanite or cubic zirconia.
Which is cheaper to produce, HPHT or CVD?
Costs vary by grower and equipment, but CVD chambers are generally less specialized and easier to scale than HPHT presses, which is part of why CVD has become common for larger production runs. Neither method changes what you pay at retail in a simple way — cut, color, and clarity drive price more than growing method.
Can you tell HPHT and CVD diamonds apart just by looking?
Not with the naked eye. Both methods produce a genuine diamond with the same brilliance and hardness; telling them apart typically takes lab equipment that reads growth patterns invisible to a jeweler's loupe. For everyday buying decisions, the growing method matters far less than the stone's cut, color, and clarity grade.
Does MYNSU sell lab-grown diamonds?
Not yet — MYNSU's current catalog is moissanite set in 925 sterling silver, a separate diamond simulant rather than a lab-grown diamond. If you want a similar sparkle today at a lower price point, our moissanite rings are the current option — lab-grown diamonds are not yet part of the catalog, though that may change.
How is a lab-grown diamond different from moissanite?
A lab-grown diamond is carbon, chemically identical to a mined diamond, just grown in a lab instead of underground. Moissanite is silicon carbide, a completely different mineral that only imitates a diamond's look — a simulant, not a diamond, even though it is also grown in a lab rather than mined from the earth.
Every MYNSU ring ships free within the US, backed by 30-day returns, from our warehouse in Irvine, California. Browse the full moissanite rings collection to compare styles while you decide what's right for you.