There is a lot of noise about lab-grown diamonds: are they real, are they worth it, will they last? This guide cuts through it. Read it once and you will know more than most people behind a jewellery counter.
What is a lab-grown diamond?
A lab-grown diamond is a diamond made by people instead of by nature. It is pure carbon arranged in the same crystal structure as a mined diamond, so it has the same hardness, the same sparkle and the same chemical make-up. It is not a lookalike like cubic zirconia or moissanite. It is diamond.
How are they made?
There are two main methods:
- HPHT (high pressure, high temperature) recreates the conditions deep in the earth, squeezing carbon around a small diamond seed at extreme heat and pressure until a crystal forms.
- CVD (chemical vapour deposition) places a diamond seed in a chamber filled with carbon-rich gas. The gas is heated until carbon atoms settle on the seed and build up the crystal layer by layer.
Either way, the rough crystal is then cut and polished by hand, exactly like a mined diamond.
Lab-grown vs mined at a glance
- Look: identical to the eye.
- Hardness: both 10 on the Mohs scale.
- Grading: both graded on the same 4Cs by labs such as IGI and GIA.
- Origin: a lab instead of a mine, with a shorter and more traceable supply chain.
- Price: lab-grown is usually far less expensive for the same size and quality.
The 4Cs, quickly
Cut controls sparkle and matters most. Colour runs from D (colourless) downwards. Clarity measures tiny inclusions. Carat is weight. Because lab-grown diamonds are more affordable, most buyers can choose a high grade in all four without stretching their budget.
Will a lab-grown diamond last?
Yes. It will not cloud, fade or lose its sparkle over time. Like any diamond, it can chip if it takes a hard knock at the wrong angle, so a sensible setting and occasional cleaning are all it needs. Read our everyday wear guide for more.
What about resale value?
This is the honest catch. Lab-grown diamonds have little resale value, and prices for new stones have fallen over the past few years as production has grown. Buy one because you love it and want to wear it, not as an investment. The same advice applies to most jewellery, mined or not.
How to buy with confidence
- Ask whether the stone is graded by an independent lab, and see the report.
- Check that the gold is hallmarked.
- Prioritise cut over carat.
- Ask about resizing, servicing and what happens if you need help later.
Still have questions? Our FAQ page covers the most common ones, or you can browse our rings, earrings and bracelets.
