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How Are Diamonds Grown in a Lab? Clarifying the Science

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How Are Diamonds Grown in a Lab? Clarifying the Science

Are you ready? We're about to go scientific.

Let's look at how Diamonds are made in Nature. 

Contrary to once popular belief, diamonds are not made from coal. Over 150km below the earth's surface, extremely high pressure and high temperature (over 1000°C) conditions are found, which transforms carbon into diamonds. Finding them closer to the surface, where they are mined, means they were brought up by a deep source volcanic eruption (a rare occurrence). Most diamonds, therefore, are mined from the biggest man-made holes that can be seen from space - not the most environmental method (read our post on traditional diamond mining).

How can we replicate the natural process with lab diamonds?

In a laboratory, gem quality diamonds with the same physical chemical and optical properties as mined diamonds, are made via two methods: Chemical Vapour Deposition (CVD) and High Pressure - High Temperature (HPHT). The different processes are suitable for creating different sizes and colours.

Chemical Vapour Deposition (CVD) diamonds are grown in a vacuum chamber. First, thin diamond plates are placed inside this chamber, followed by hydrocarbon gas and hydrogen. High power microwaves then react with the gas, converting some of the hydrogen to atomic hydrogen, which in turn reacts with the gas to create activated carbon-hydrogen. This new carbon-hydrogen then bonds to the carbon atoms in the diamond plates, causing that diamond plate to grow into rough diamonds.

Still with us? Let's move on to the more traditional method. 

High Pressure - High Temperate (HPHT) diamonds are created in what are essentially giant pressure cookers. Small diamond 'seeds' are placed in a chamber, with crystallised carbon - graphite. Next, extreme temperate (1300-1600°C) and pressure are applied, resulting in the graphite melting into liquid carbon. This begins to form around the diamond seed, which is then carefully cooled into a diamond crystal. 

So, which method is best?

Since these technologies are mimicking nature, the diamonds created will still have variations in colour and clarity. Lab created doesn't mean 'perfect'. Both CVD and HPHT have their pros and cons, as manufacturers strive to create higher quality, bigger stones. 

Some larger stones are actually created using a combination of CVD and HPHT to ensure premium quality, colour and light performance. As the industry grows, new technologies may come into play that use even less resources or create even larger stones.

In fact, a lot of mined diamonds on the market have actually undergone a HPHT process. This allows manufacturers to purchase flawed or discoloured diamonds and then use HPHT to alter them to a better quality. So, even if you are being sold a ‘natural’ diamond, chances are there was a lab involved.

Mined diamond sellers often try to discredit lab diamonds by calling them 'synthetic diamonds', to fool customers into thinking they are the same as Cubic Zirconia. In reality, regardless of the different processes of creating diamonds in a lab, both produce 100% real diamonds (read our post introducing lab diamonds).

In that case, does it matter where my lab diamond comes from?

Yes, absolutely.

Just like natural diamonds, a lab diamond's journey doesn't end once it has been created. This diamond 'rough' needs to be cut and polished into a finished stone. As discussed in our prior post, 90% of gems on the global market are cut and polished in areas where there are large instances of poor labour conditions.

AïANA was born based on research and education to seek out suppliers, cutters and makers in line with our 'conscious choice' value. 

Do your research regardless of whether you are purchasing natural or lab diamonds, if you want to purchase sustainable and ethical pieces. 

Knowledge is Power.