Lab-grown diamonds are not a new phenomenon, despite what the media may have you believe. Since the 1950’s, both De Beers and General Electric have been manufacturing synthetic diamonds, purely for industrial applications (for example drill bits, cutting saws & polishing wheels). These synthetic diamonds, mostly tiny (2mm in size) bright yellow cubo-octahedral crystals, were never considered to be a threat to natural diamonds, and stayed firmly in the corner of industrial use.

Lab-grown synthetic diamonds

Lab-grown industrial quality diamonds tend to be bright yellow, with cubo-octahedral crystal shapes.

Over the last 10 years however, laboratory-grown diamonds have made in-roads into the retail diamond industry, resulting in responses of concern, consternation and fear from the jewellery trade.

More and more online jewellery retailers (particularly in the USA) are starting to advertise man-made diamonds, lab-grown diamonds and cultured diamonds as a viable alternative for natural diamonds. But, how do lab-grown diamonds compare with “the real thing”?

For the purposes of this article, we will use the terms “lab-grown diamonds” and “man-made diamonds” interchangeably.

How do you make a man-made diamond?

There are two primary ways to grow diamonds under artificial laboratory conditions. The most popular method is known as HPHT (High Pressure, High Temperature), which is an attempt to replicate the exact conditions that diamonds grow under in the Earth’s mantle. With required pressures of over 5 GPa and temperatures of over 1500°C, this is not an easy task. To start the diamond growth process, a “seed” is needed, upon which successive layers of carbon are grown.

The second, and less common, growth process is known as CVD (Chemical Vapour Deposition) and, as crystal growth occurs in flat wafers, CVD diamonds are rarely used in jewellery applications. Instead, CVD diamonds have extensive application potential in semi-conductor and optical instruments.

Initially, lab-grown diamonds tended to be of an inferior quality to natural, gem-quality diamonds but over the last few years, as technology has progressed, lab-grown diamonds are being manufactured in qualities equivalent to gem-quality diamonds.

How does a lab-grown diamond differ from a natural diamond?

The short answer is that it doesn’t. Just as natural diamonds are 100% pure Carbon, so are man-made diamonds. Atom for atom, the crystal structure is the same, and the composition is the same, meaning that the physical properties are identical. Unlike diamond simulants like cubic zirconia or moissanite, a man-made diamond is a diamond. It’s just grown in a laboratory as opposed to the mantle of the Earth.

Man-made diamond earrings

These diamond earrings are set with 100% lab-grown diamonds. They look identical to natural diamonds, don’t they?

As such, all visible features of a lab-grown diamond are identical to those of a natural diamond. They cut and polish the same way, they reflect and refract light the same way, they conduct electricity the same way, and they look exactly the same when set in jewellery. There are no differences visible to the naked eye.

How do you know if a diamond is natural or man-made?

There are a number of subtle differences between diamonds grown deep in the mantle of the earth compared to those grown in laboratories above the ground. However, to spot these differences you need some fairly expensive analytical equipment.

One of the ways to differentiate a man-made diamond from a natural diamond is to run a Fourier Transform Infrared Spectroscopy (FTIR) scan. This analysis measures the amount of hydrogen and nitrogen in a diamond, and approximately 95% of natural diamonds contain some proportion of nitrogen and hydrogen. Typically, man-made diamonds will contain neither nitrogen nor hydrogen.

Lab-grow diamond FTIR

A graphical comparison of the IR spectroscopy of a natural diamond vs a synthetic diamond.

A small proportion (approximately 2%) of natural diamonds are known as Type IIa diamonds, meaning they have no distinguishable nitrogen. Most man-made diamonds are Type II a diamonds, so if a diamond of uncertain origin tests as a Type IIa diamond, it will be flagged as a possible man-made stone and referred for further testing.

Another way to distinguish a man-made diamond from a natural diamond is by testing the stone’s surface fluorescence. De Beers have developed the “Diamond View” machine which uses short-wave ultra-violet light to test fluorescence. Man-made and natural diamonds will exhibit differences in the colour of the fluorescence, the fluorescence pattern and the absence or presence of phosphorescence.

HPHT Lab-grown diamond

A De Beers Diamond View scan of a lab-grown HPHT diamond showing typically blocky, synthetic growth patterns. Source: IIDGR

What does a lab-grown diamond cost?

When lab-grown diamonds first became available in the jewellery market, they were relatively expensive, and offered, on average, a saving of only 30-40% off the cost of a natural diamond. For many people, this price difference wasn’t enough to convince them to purchase a man-made diamond.

Then, in early 2018, De Beers made a startling announcement that turned the lab-grown jewellery industry on its head. After pledging to never compete in the lab-grown diamond jewellery arena, De Beers announced the launch of a new company (under the De Beers Group umbrella), called Lightbox.

With a USA-only launch planned for later in 2018, De Beers announced that they would be selling their own lab-grown diamonds, in colourless, blue and pink hues, for $800 per carat. With one clean swipe, De Beers had pulled the carpet out from under its lab-grown diamond competitors. Now, lab-grown diamond companies would be forced to bring down their prices to compete with De Beers. Overall, the production costs of lab-grown diamonds have dropped over the last few years and in South Africa, lab-grown stones sell for about half the price of natural diamonds.

Are lab-grown diamonds eco-friendly?

Many jewellery companies are marketing lab-grown diamonds using generic terms such as “eco-friendly”, “sustainable” and “ethical”. Whilst this kind of advertising has been prevalent in the United States, we’ve seen some South African jewellery manufacturers using the same terms on their websites, Facebook and Instagram profiles. Unfortunately, the use of these terms is misleading, particularly when not used in conjunction with either “lab-grown” or “man-made”.

This is such a serious concern to the diamond industry that in the USA, the Federal Trade Commission (FTC) has issued warnings to 8 jewellery brands over misleading sustainability claims in their advertising. The FTC wants companies to make it clear to their customers that what they are purchasing is a man-made diamond, not a natural diamond.

Lab-grown diamond carbon intensity

Lab-grown, or synthetic, diamonds have a carbon intensity far higher than you’d expect. Source: Reuters Graphics

There is no conclusive data proving that lab-grown diamonds are either eco-friendly or sustainable and, indeed, early research has shown that the manufactured diamond industry has misappropriated these terms. The founder of one lab-grown diamond manufacturer has admitted that the “most efficient” growth laboratories use 250 kWh (Kilowatt Hours) to produce one carat (1ct) of diamond. This is the same amount of electricity that the average American household uses in 8.7 days.

To compare, De Beers’ global mining operations (for the mining and recovery of natural diamonds), uses 80.3 kWh to produce a carat of diamond. Further research has indicated that the carbon intensity of man-made diamonds is significantly higher than that of natural diamonds.

Should I buy a lab-grown diamond?

At the end of the day, it comes down to what decision each individual consumer wants to make. There is inherently nothing wrong with lab-grown diamonds, provided you know that is what you are buying. The problem comes in when you have an unethical jeweller who sells you a man-made diamond pretending that it’s a natural diamond.

There will never be a shortage of man-made diamonds, nor will they ever have the perceived mystery and intrigue that natural diamonds possess. There are some customers who don’t mind the thought of lab-grown diamonds for a pair of earrings, or a diamond pendant, but they’d never dream of purchasing a lab-grown diamond for an engagement ring. That’s where many customers still want real, natural diamonds.

Where can I buy a man-made diamond?

Call them what you will – man-made, cultured or lab-grown diamonds – these diamonds appear to be a growing market segment in South Africa.

IGI Laboratory certificate for lab-grown diamonds available in South Africa from Katannuta Diamonds.

These lab-grown diamonds are IGI-certified and laser engraved with “Laboratory Grown” and a certificate number, meaning there is no confusion about the origin of these diamonds. If you’d like more information on where you can purchase lab-grown diamonds please contact us with your specific requirements and we’ll refer you in the right direction.