Growing a lab grown diamond takes anywhere from 6 days to 6 weeks, depending on the method and the carat size. HPHT diamonds form faster, often within 10 days for a 1-carat stone. CVD takes longer, typically 3 to 4 weeks for the same size, but produces purer, Type IIa quality crystals. Natural diamonds, by comparison, take billions of years underground.
The method does not affect the final quality. Both produce real, IGI-certifiable diamonds. What changes is the process, the purity profile, and the time.
What Is a Lab Grown Diamond?
A lab grown diamond is a real diamond, not a simulant like cubic zirconia or moissanite. It shares the same carbon structure, hardness, and brilliance as a mined diamond; the only difference is where it forms, in a controlled lab using CVD or HPHT technology instead of billions of years underground. Every House of Quadri stone carries an IGI certificate confirming this.
How Long Does It Take to Grow a Diamond?
Most lab grown diamonds take 1 to 6 weeks to form. HPHT is generally faster, while CVD takes longer but produces purer, Type IIa quality crystals. Carat size is the biggest factor; larger stones need more time for carbon to build up layer by layer.
CVD Diamond Formation Timeline
Chemical Vapour Deposition places a diamond seed in a sealed chamber filled with carbon-rich gas. The chamber is heated until carbon atoms separate from the gas and settle onto the seed, layer by layer.
- A 1-carat rough diamond typically takes 3 to 4 weeks
- This slow, controlled build is why CVD is preferred for Type IIa diamonds, the purest diamond category
HPHT Diamond Formation Timeline
High Pressure High Temperature recreates the Earth's natural conditions directly. A carbon source is subjected to temperatures above 1,400°C and pressure exceeding 1.5 million pounds per square inch, forcing carbon atoms into a crystal structure.
- A 1-carat rough diamond usually forms in 6 to 10 days
- HPHT is also used to enhance the colour of existing diamonds
Why Is HPHT Faster Than CVD?
HPHT compresses carbon under extreme pressure the same way nature does underground, so the crystal forms almost immediately once conditions are reached. CVD instead builds the stone from gas one atomic layer at a time, roughly 0.1 to 0.5 mm per day, slower but with finer control over purity. That mechanism, not equipment quality, is why one method consistently outpaces the other.
Growth Time by Carat Size: CVD vs HPHT
Timelines shift once carat size increases, since larger stones need more carbon deposited before the crystal is ready.
| Carat Size | CVD Growth Time | HPHT Growth Time |
|---|---|---|
| 1 carat | 3 to 4 weeks | 6 to 10 days |
| 2 carat | 4 to 5 weeks | 10 to 15 days |
| 3 carat and above | 5 to 6+ weeks | 3 to 4 weeks |
From Rough Diamond to Finished Jewellery
Growth is only part of the wait. Every rough diamond still needs cutting, polishing, and certification before it's wearable.
- Cutting and polishing: shapes the stone and refines each facet for brilliance
- IGI certification: verifies cut, colour, clarity, and carat
- Setting: the certified diamond is set in 18K hallmarked gold
This is why House of Quadri quotes roughly 3 weeks for delivery.
Does a Faster Timeline Mean Lower Quality?
Not at all. Growth time affects the process, not the outcome. CVD and HPHT diamonds are chemically and optically identical to mined diamonds, and every House of Quadri diamond is IGI certified regardless of method. Our page on common misconceptions around lab grown diamonds breaks down where that idea comes from.
Why the Timeline Matters for Buyers
A shorter production cycle is one reason lab grown diamonds cost less than mined stones of equal size and clarity. Our guide on why lab-grown diamonds are more affordable breaks down the cost drivers, and you can browse our ring collection once you've decided.
Conclusion
Whether it's grown in 6 days or 6 weeks, a lab grown diamond ends up chemically and visually identical to one pulled from the earth, just without the wait or the environmental cost. The CVD vs HPHT timeline mostly helps set expectations, not judge quality, and at House of Quadri, every stone carries its IGI certificate regardless of which method grew it.
FAQs
How long does it take to grow a 1-carat diamond?
A 1-carat CVD diamond takes 3 to 4 weeks, while HPHT produces a comparable stone in 6 to 10 days.
Is CVD or HPHT faster for growing diamonds?
HPHT is faster at every carat size. CVD takes longer but is preferred for Type IIa purity.
Do lab grown diamonds take less time than natural diamonds?
Yes, significantly. Natural diamonds form over billions of years underground, while lab-grown diamonds are ready in days to weeks.
Which method does House of Quadri use?
We grow diamonds using both CVD and HPHT, depending on the design and diamond category required.
Does growth time affect diamond durability?
No. Both CVD and HPHT diamonds score 10 on the Mohs hardness scale, identical to mined diamonds.
