Lab-grown diamonds — also known as cultivated diamonds — are formed in highly controlled laboratory environments using advanced technology that replicates and accelerates the natural diamond-growing process. Just like those formed deep within the Earth’s mantle, these diamonds are made of pure carbon arranged in a cubic crystal structure.
Are lab-grown diamonds real diamonds?
Perhaps the most common question people ask about lab-grown diamonds is: Are they real? The answer is a definitive YES. Lab-grown diamonds are chemically, physically, and optically identical to mined diamonds — because they are diamonds.
Just like natural ones, each lab-grown diamond is unique, with its own variations in colour, clarity, and cut. Many even contain tiny inclusions — natural features that form as the diamond grows. The only way to tell a lab-grown diamond from a mined one is with specialised gemmological equipment that can detect subtle differences in trace elements or growth patterns.
Lab-grown diamonds are not to be confused with moissanite or cubic zirconia, which whilst also made in labs, don’t share a true diamond’s durability or enduring sparkle. Cubic zirconia is significantly softer than diamond and will scratch and become cloudy over time with regular wear—often within a few years. Whereas moissanite, whilst almost as hard as a diamond (measuring 9.25 on the Mohs scale of hardness, compared to a diamond’s perfect 10), has a different refractive index. This means it bends and reflects light differently, producing a rainbow-like, almost “disco ball” effect rather than a diamond’s crisp, white brilliance.
Diamonds — whether natural or lab-grown — retain their clarity and sparkle for a lifetime, often becoming treasured heirlooms.
How natural diamonds are formed
Natural diamonds were forged deep within the Earth, under conditions of intense heat and pressure, billions of years ago. For a long time, people have assumed that diamonds always take millions of years to form — but this may not be entirely true. According to research by the Smithsonian Institution, diamonds can form over vastly different timescales — from days or months to millions of years — depending on the precise temperature, pressure, and chemical environment in the mantle.
What is clear, however, is that most of the diamonds we find today are very old. Scientists believe they formed when the Earth was hotter and more geologically active — a period when conditions were ideal for diamond growth. Many of these gems are thought to be between one and three billion years old, making them some of the oldest natural materials on Earth. [1]
How are lab-grown diamonds cultivated?
Lab-grown diamonds are created using one of two methods, both beginning with a seed — a tiny slice of an existing diamond.
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High Pressure High Temperature (HPHT):
This process mirrors the intense natural conditions under which diamonds form deep underground. Carbon is exposed to pressures of around 725,000 psi (5 GPa) and temperatures of about 1,500°C, encouraging carbon atoms to bond and grow around the diamond seed. -
Chemical Vapor Deposition (CVD):
In this method, the diamond seed is placed in a sealed, carbon-rich vacuum chamber. A plasma of ionised carbon gas forms, and carbon atoms gradually deposit onto the seed layer by layer, growing a new diamond crystal.
Whether grown by HPHT or CVD, lab-grown diamonds are then cut, polished, evaluated and graded by the same gemological labs that certify mined diamonds, using the same strict standards.
| Properties | Lab-Grown Diamonds | Mined Diamonds |
|---|---|---|
| Hardness (MOHS) | 10 | 10 |
| Guaranteed Conflict-Free | Yes | No |
| Chemical Composition | Carbon | Carbon |
| Refractive Index | 2.42 | 2.42 |
| Crystalline Structure | Cubic | Cubic |
Lab-grown vs natural, which is right for you?
Whilst they may be physically and chemically identical their impacts are not. Like all things on this complicated blue-green planet of ours the full story is a long one. Read our journal entry on the social and environmental impact of lab-grown versus natural diamonds here.
This blog post was edited 30 October 2025 with additional information and to keep up with technical developments in the lab-grown diamond industry.
References:
[1] https://www.smithsonianmag.com/science-nature/diamonds-unearthed-141629226/