CVD vs HPHT Diamonds: What Changes in Look, Purity, and Price?

Lab grown diamond jewellery has become the most genuine expression of conscious luxury. But within lab grown diamonds itself, there's a distinction that doesn't get nearly enough attention, and it starts with how the diamond was actually born.

CVD Diamonds: Grown from Carbon, One Layer at a Time

Chemical Vapour Deposition is a process where a diamond seed is placed inside a sealed chamber filled with carbon-rich gas. 

That gas is then ionised into plasma, and carbon atoms begin to settle onto the seed and crystallise slowly, precisely, one layer at a time. 

It's a process that rewards patience, and the diamonds it produces tend to reflect that.

The Diamond’s Look: The controlled environment means fewer interruptions during growth, and that shows in the finished stone. CVD diamonds are typically colourless and visually clean. It’s the kind of clarity that sits well in fine jewellery without needing much else to carry it.

The Diamond’s Purity: Here is where CVD sets itself apart. It produces a notably high proportion of Type IIA diamonds, a classification defined by the near-total absence of nitrogen, and one of the rarest in terms of brilliance and purity. CVD earns its place for Type IIA diamond production more consistently than any other method.

The Diamond’s Price: CVD diamonds are generally the more accessible of the two. The technology has matured, the process scales well, and you will find that the value relative to quality is genuinely hard to argue with.

HPHT Diamonds: Where Geology Gets a Push

High Pressure High Temperature is a process where the diamond seed is exposed to pressures and temperatures that mirror what happens deep within the earth, somewhere around 1,400 degrees celsius and beyond. 

Carbon crystallises around the seed, and a diamond forms.

The Diamond’s Look: HPHT diamonds can carry a faint yellow or blue tint, depending on the trace elements present during growth. Colourless HPHT stones do exist, but they require more deliberate selection at the grading stage.

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The Diamond’s Purity: Most HPHT diamonds fall into the Type IB category, which means they carry measurable nitrogen. That's not a disqualifier, but it is a meaningful difference.

The Diamond’s Price: The equipment is costly and the process is energy-heavy, which tends to show in the price at times, particularly for colourless, high-clarity stones. Diamond price factors here are directly tied to how much the method demands at every stage.

CVD vs HPHT Diamond: Side by Side

Features	CVD	HPHT
Growth Method	Carbon vapour deposited in a controlled chamber	Extreme pressure and heat mimicking earth's mantle
Typical Colour	Colourless to near-colourless	Can show faint yellow or blue tints
Diamond Clarity	Consistently high	Variable and colourless stones need careful grading
Diamond Type	Frequently Type IIA	Most commonly Type IB
Nitrogen Content	Near absent	Present in most
Price	Generally more accessible	Might be higher for colourless, high-clarity diamonds

visit for more information: Certified Lab Grown Diamonds Pure CVD Technology – Limelight Diamonds

What You Should Choose

Go for CVD diamonds if colourless brilliance, optical purity, and exceptional value for quality are what you're after.

Go for HPHT diamonds if you're drawn to fancy coloured stones.

Both are lab grown diamonds, graded, and worthy of the jewellery they end up in. The difference, as with most things in this world, is in the details.

For those who've read through all of this and find themselves leaning toward purity and brilliance that matches the Koh-I-Noor, a type IIA diamond then Limelight Diamonds might just be what you’re looking for. 

They work solely with Type IIA CVD certified lab grown diamonds. It's a deliberate choice, and one that makes every piece of diamond jewellery they craft extraordinary and something you can cherish forever.