How to Identify HPHT vs CVD Diamonds
Two methods, one beautiful result. Here's what actually distinguishes HPHT and CVD diamonds.
Lab grown diamonds are created either by HPHT or CVD. Both produce real diamonds, and once they're cut and polished you can't tell them apart by eye. But there are some technical differences worth knowing.
The honest answer: you can't tell at home
For a finished, polished diamond, distinguishing HPHT from CVD requires specialized gemological equipment. Neither looks better to the naked eye — both are equally real and brilliant. Only a lab can say for certain.
What labs look at
| Clue | What it can indicate |
|---|---|
| Growth pattern | CVD shows layered striations; HPHT shows an angular pattern. |
| Metallic inclusions | Tiny metal flux traces can point to HPHT. |
| Fluorescence | The two can react differently under UV in lab conditions. |
What actually matters to you
For a buyer, the growing method rarely matters — what counts is the 4Cs and a reputable certificate. Ask for an IGI or GIA report, which states whether a stone is lab grown. More in Certification: GIA vs IGI.
New to the two methods? Start with What Is an HPHT Diamond? and What Is a CVD Diamond?
FAQs
Can I tell HPHT from CVD myself?
No — it takes specialized lab equipment; both look identical once polished.
Does it matter which method made my diamond?
Not really — both are real diamonds. Focus on the 4Cs and a trusted certificate.
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