CVD vs HPHT Diamonds Key Differences Malaysian Buyers Should Know

When shopping for a diamond, you may come across two terms that are worth understanding: CVD and HPHT. Both describe methods used to grow diamonds in laboratories, but the processes behind them are quite different. If you are comparing jewellery options in Malaysia, knowing how these methods work can help you make a more informed choice.

The difference is not simply about how a diamond is made. Each process can affect the crystal’s growth patterns, possible inclusions and the treatments it may receive after production. However, neither method automatically produces a better-looking diamond.

For buyers considering lab grown diamonds, the most useful approach is to understand the production process and then compare the finished stones on their individual qualities.

What Happens During the HPHT Diamond Process?

HPHT stands for High Pressure High Temperature. This method recreates some of the conditions found deep inside the Earth, where natural diamonds develop over long periods.

The process starts with a small diamond seed and a carbon source, usually graphite. These materials are placed inside a specialised growth chamber. The equipment then applies extremely high pressure and temperatures, generally around 1,300–1,600°C.

A metal mixture helps dissolve the carbon. As the carbon moves towards the cooler diamond seed, it begins to crystallise and form a larger diamond. Depending on the required size and quality, the growth process can take anywhere from several hours to a few weeks.

HPHT has been used to produce gem-quality diamonds for decades. It can also produce coloured diamonds. For example, adding boron during growth can create blue diamonds, while nitrogen can contribute to yellow colouring.

How CVD Creates a Diamond Crystal

CVD stands for Chemical Vapour Deposition. Instead of using extreme pressure, this method grows diamonds inside a controlled vacuum chamber.

A small diamond seed is placed inside the chamber, which is filled with gases containing carbon, commonly methane, along with hydrogen. Energy from microwaves breaks down these gases into smaller particles. Carbon atoms then settle onto the diamond seed, gradually building new layers of diamond.

Unlike HPHT, which grows crystals through a metal-based process, CVD builds the diamond layer by layer. The chamber may need to be opened during production so that unwanted graphite can be removed before growth continues.

This process often takes several weeks. The resulting crystal usually has a flat, plate-like shape before it is cut and polished for jewellery.

Some CVD crystals develop a brown or yellowish colour during production. Manufacturers may use an additional treatment to improve the final colour. This is an important detail to check when comparing stones.

CVD vs HPHT: Main Differences at a Glance

Although both methods create real diamonds, their production techniques and some internal features are different.

These are general characteristics rather than fixed rules for every diamond. The final result depends on the growth conditions, seed quality and any treatments applied afterwards.

Does CVD or HPHT Produce Better Diamond Quality?

This is one of the most common questions buyers ask when comparing the two methods. The simple answer is that the growth method alone cannot tell you which diamond is better.

A well-grown CVD diamond can have excellent colour and clarity. The same applies to an HPHT diamond. Both can be cut into popular shapes, including round, oval, pear, emerald and cushion.

Instead of choosing based only on the production label, pay attention to the four main diamond characteristics:

• Cut: Affects how well the diamond reflects light. A well-cut stone can look lively and bright.

• Colour: Refers to how colourless or tinted a white diamond appears. Compare the actual colour grade.

• Clarity: Describes internal inclusions and surface marks. Check whether any visible features affect the appearance.

• Carat: Measures the diamond’s weight, not its physical dimensions or visual quality.

For an engagement ring, the cut and overall appearance may matter more to you than whether the stone was grown using CVD or HPHT.

Why Some CVD Diamonds Receive HPHT Treatment

One detail that often creates confusion is the use of HPHT treatment on a CVD diamond.

Growing a diamond through HPHT and treating an already-grown CVD diamond are two different processes. During treatment, the existing crystal is exposed to high temperatures and controlled conditions to improve its colour. No additional diamond material is created.

According to GIA’s 2024 research, approximately 80% of the CVD diamonds submitted to its laboratories since 2020 showed signs of post-growth processing. This highlights why treatment information matters when comparing stones.

It does not mean that a treated diamond is automatically poor quality. What matters is knowing what has been done to the stone and whether the treatment has been properly disclosed.

Can You Tell CVD and HPHT Diamonds Apart?

To the naked eye, it is usually difficult to identify whether a polished diamond was grown using CVD or HPHT. Both methods produce genuine diamonds with the same basic chemical composition and crystal structure as natural diamonds.

Gemological laboratories use specialised equipment to examine internal growth patterns, inclusions and reactions under ultraviolet light.

For example, HPHT diamonds may contain tiny metallic inclusions from the metals used during production. CVD diamonds can show distinctive banded strain patterns or small dark inclusions. These features help trained gemologists identify the growth method, although not every stone displays the same characteristics.

This is why buyers should not rely on appearance alone. A grading report from a recognised gemological laboratory can provide useful information about a diamond’s identity and characteristics.

What Should Malaysian Buyers Check Before Purchasing?

Shopping for a diamond in Malaysia gives buyers access to different jewellery styles, settings and stone specifications. However, it is worth looking beyond the advertised carat weight or the words CVD and HPHT.

Here are a few practical points to consider before making a purchase:

• Ask about the growth method: Confirm whether the diamond was originally grown using CVD or HPHT.

• Check treatment details: If a CVD diamond received HPHT colour treatment, ask whether this information is disclosed.

• Review the grading report: Look for details about the diamond’s colour, clarity, cut and carat weight.

• Compare actual appearance: If possible, view both stones under similar lighting conditions. Check their sparkle, colour and visible inclusions.

• Understand the jewellery setting: The metal, prong design and setting style also affect the finished appearance and everyday wear.

If you are comparing different designs, Novita Diamonds Malaysia is a relevant place to consider when researching diamond jewellery options. Take time to compare individual stone specifications rather than assuming one growth method is always the better choice.

It is also worth checking the retailer’s return policy, warranty conditions and after-sales support. These details can make a difference if you are buying an engagement ring or another piece intended for regular wear.

A useful starting point is to compare the available specifications and jewellery designs at Novita Diamonds Malaysia before deciding which diamond suits your preferences.

Which Growth Method Should You Choose?

There is no universal winner in the CVD vs HPHT comparison. Both methods have developed considerably, and both can produce diamonds suitable for fine jewellery.

CVD may appeal to buyers interested in diamonds grown through a layer-by-layer process, while HPHT offers a different production approach based on pressure and heat. Neither method guarantees superior cut, colour or clarity.

For Malaysian buyers, the finished diamond should be the main consideration. Compare its grading information, appearance, treatment history and price. Once you understand these details, choosing between CVD and HPHT becomes a much more straightforward decision.