CVD and HPHT are the two main ways lab-grown diamonds are created. Both produce real diamonds of the same quality. For buyers, the production method matters far less than the certificate, the 4Cs, and the overall craftsmanship of the piece.
What Is a CVD Diamond?
What Is a CVD Diamond?
CVD stands for Chemical Vapour Deposition. In this process, a thin slice of diamond (called a seed crystal) is placed inside a sealed chamber. The chamber is filled with carbon-rich gases — typically methane — and heated to very high temperatures. The carbon atoms in the gas break down and gradually attach to the seed crystal, layer by layer, building up into a full diamond over several weeks.
CVD diamonds are widely used in the fine jewellery industry and can produce stones of very high quality, including excellent colour grades. Most lab-grown diamonds sold in India today are CVD.
What Is an HPHT Diamond?
What Is an HPHT Diamond?
HPHT stands for High Pressure High Temperature. This process replicates the conditions found deep inside the earth — intense heat (around 1,500°C) and enormous pressure — applied to a carbon source and a diamond seed crystal. Under these conditions, the carbon melts and solidifies around the seed, forming a diamond.
HPHT diamonds can also be produced in high quality. This method is additionally used to improve the colour of diamonds that have already been formed — including some natural diamonds — through a controlled heat-and-pressure treatment.
Is CVD Better Than HPHT?
Is CVD Better Than HPHT?
Neither is inherently better than the other. Both methods can produce high-quality, fully certifiable diamonds. The final quality of a diamond — whether CVD or HPHT — is determined by the 4Cs: cut, colour, clarity, and carat weight. These are assessed and graded the same way regardless of how the diamond was grown.
A well-cut, high-colour CVD diamond is not superior to a well-cut, high-colour HPHT diamond. And vice versa. The method is a technical detail — the certificate is what matters.
What Should Buyers Check?
What Should Buyers Check?
When buying a lab-grown diamond, focus on:
- The certificate — SGL or IGI are the most recognised in India
- Diamond origin (should clearly state "laboratory grown")
- Cut, colour, and clarity grades
- Carat weight
- Gold purity and BIS hallmark on the jewellery
Whether the diamond is CVD or HPHT is a secondary consideration. What matters is the quality of the stone and the transparency of the documentation. For a full guide on what to look for, read our complete comparison of lab-grown and natural diamonds.
