Melbourne client care · Made in Surat
Two processes produce every lab grown diamond: High Pressure High Temperature (HPHT) and Chemical Vapour Deposition (CVD). Both create genuine diamonds. This guide explains each process in detail — the science behind them, how they differ, what they produce and which Fenora uses and why.
Both HPHT and CVD diamond growth begin with the same thing: a diamond seed. This is a small slice of existing diamond — typically a few millimetres across — that provides the crystal template for the new diamond to grow from. The diamond seed establishes the crystal orientation and structure that the new diamond will follow as it forms.
The seed can be a natural diamond or a previously grown lab diamond. The origin of the seed does not affect the quality of the finished stone — the new diamond grows from the seed's crystal structure, not from its material.
From this starting point, the two processes diverge significantly: HPHT uses extreme mechanical pressure and heat to replicate the geological conditions under which natural diamonds form. CVD uses chemistry — a gas plasma — to deposit carbon atoms onto the seed layer by layer, like a controlled version of crystal growth from vapour.
HPHT diamond growth replicates the conditions deep within the Earth where natural diamonds form — extreme pressure and extreme temperature, applied to carbon in the presence of a metal catalyst.
CVD diamond growth takes a completely different approach. Instead of extreme pressure, CVD uses chemistry — a carbon-rich gas is broken down in a plasma chamber, and the carbon atoms deposit onto a diamond seed layer by layer, building the crystal from the bottom up.
How the two growth methods compare across every relevant dimension.
| Dimension | HPHT | CVD |
|---|---|---|
| How it works | Extreme pressure and temperature — geological simulation | Gas plasma chemistry — layer-by-layer deposition |
| Pressure required | ~1.5 million PSI | Minimal — near-vacuum chamber |
| Temperature | 1,400–1,600°C | ~700–1,200°C (lower than HPHT) |
| Growth time | Days to weeks | Weeks to months |
| Energy use | Very high | Lower than HPHT — more energy efficient |
| Typical inclusions | May include metallic inclusions from catalyst | Typically cleaner — fewer inclusions |
| Size capability | Larger sizes more readily available | Growing capability but historically smaller than HPHT at scale |
| Post-growth treatment | Not typically required | Sometimes HPHT treated for colour improvement — legitimate and disclosed |
| IGI grading | Same scale as CVD and mined | Same scale as HPHT and mined |
| Fenora usage | Available in collection | Primary method — preferred for gem-quality stones |
| Can you tell the difference in a finished ring? | No — both are identical in appearance | No |
The lab grown rough diamond that comes out of either process looks nothing like the finished diamond in your ring. It is a crystal — often octahedral or cubic in form — that must be planned, cut and polished before it is a gem-quality stone.
Fenora's preference for CVD diamonds for gem-quality centre stones reflects specific quality and consistency advantages that matter for fine jewellery.
Common questions about how lab grown diamonds are made.
Book a free online consultation. Yash Chandpara explains the growth process of every stone presented in the consultation and identifies the method and any post-growth treatment.
