What Is an HPHT Diamond?
One of the two ways lab grown diamonds are created. Here's how the High Pressure High Temperature method works.
Lab grown diamonds are made by one of two methods: CVD or HPHT. We've covered CVD elsewhere — this is the story of HPHT, the technique that recreates the Earth's own diamond-making conditions inside a machine.
What HPHT stands for
HPHT means High Pressure, High Temperature. It mimics the natural environment deep in the Earth's mantle where diamonds form — just far faster and in a controlled setting.
How the process works
A small diamond seed and a source of carbon are placed in a chamber, then subjected to enormous pressure (around 1.5 million PSI) and temperatures above 1,400°C. The carbon melts and crystallizes onto the seed, growing a rough diamond layer by layer.
HPHT vs CVD
Both produce real, identical diamonds — the difference is method. HPHT uses pressure and heat; CVD builds crystals from carbon-rich gas. HPHT is also used to enhance the color of some diamonds. Learn about the other method in What Is a CVD Diamond?
And see how the natural version compares in How Diamonds Form in Nature.
FAQs
Is an HPHT diamond a real diamond?
Yes — it's chemically and physically identical to a mined diamond.
Is HPHT or CVD better?
Neither is “better” — both create real, high-quality diamonds; they're just different growing methods.
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