A guide to lab grown diamonds

Scientists first started to produce real diamonds in laboratories in the 1950s, but these were too small to be used in jewellery. As manufacturing methods improved, lab grown diamonds started to be produced in volume for industrial purposes. Still, it was not until the 1990s that larger, gem-quality crystals began to be produced. However, for many years producers could not prevent traces of nitrogen and other elements from entering the diamond crystals during their formation, which resulted in coloured diamonds being produced.

Finally, within the last decade, gem-quality white lab grown diamonds have become widely available, and demand for lab grown diamonds has risen dramatically.

From how they're made, to what they cost, and why you might consider choosing one over a mined diamond, we've put together this guide to answer all your questions about lab grown diamonds.

What are lab grown diamonds?

Lab grown diamonds (also known as lab created diamonds) are real diamonds that are grown in a laboratory using one of two methods. We'll get into the details of these later, but both methods imitate the process by which mined diamonds were formed beneath the earth's crust about three billion years ago and result in real diamonds made from the same element (carbon) as mined diamonds, and with exactly the same physical, chemical and optical properties as mined diamonds.

Indeed, in 2018, the US Federal Trade Commission amended its Jewelry Guides to no longer define a mined diamond by using the term 'natural' on the basis that it is no longer meaningful given that lab grown have exactly the same properties as mined diamonds.

What are the benefits of a lab grown diamond?

While lab grown and mined diamonds are physically identical, lab grown diamonds offer three main benefits over mined diamonds:

• Guaranteed conflict-free
• Lower environmental impact
• Lower cost

Let's explore each of these in a bit more detail.

Guaranteed conflict-free 

With lab grown diamonds you can be assured that your diamond has not come from a conflict zone. Unfortunately, this is not always the case for mined diamonds, which have been used to fund conflicts in some parts of Africa.

While the number of conflict diamonds or blood diamonds entering the market was significantly reduced following the introduction of the Kimberley Process in 2003, it did not eliminate the problem completely, and so there remains a risk that you could end up with a conflict stone. Canadian diamonds are a rare exception, in that these are traceable back to their mines of origin in Canada, and are therefore also guaranteed to be conflict-free.

Lower environmental impact

Mining for diamonds inevitably has a negative impact on the local environment. However, some countries are stricter than others about mitigating this impact. We offer Canadian diamonds not only because they are traceable and therefore guaranteed to be conflict-free, but because Canada also has very strict environmental legislation that requires mines to minimise and manage the impact they have on the local flora and fauna and to restore the land after the mine closes.

Growing diamonds in a lab still requires energy, but it requires much less energy per carat of diamond than mining for diamonds. And unlike mining, it is possible to create lab grown diamonds using only sustainable energy sources.

Lower cost

While lab grown diamonds and mined diamonds are physically and chemically identical, lab grown diamonds are often much more affordable. In fact, they're typically 40-70% less expensive than a mined diamond. 

The price difference is partly down to production costs, since growing a diamond in a lab is much more cost-effective than mining for one. But it is also because the supply of mined diamonds is much more constrained, which serves to inflate their prices.

How are lab grown diamonds made?

There are two methods for creating a lab grown diamond:

• High pressure high temperature (HPHT)
• Chemical vapour deposition (CVD) 

High-pressure high-temperature (HPHT) method

HPHT is the original diamond growth method and creates diamond crystals under conditions that mimic those in which mined diamonds were formed within the earth.

This process begins with a diamond 'seed' (a tiny diamond crystal) being placed inside a small chamber within an HPHT "press", along with carbon in the form of graphite, and some metals such as iron, nickel or cobalt, which act as a catalyst, reducing the temperature and pressure needed for diamond growth.

The pressure within the chamber is raised to more than 60,000 atmospheres and the temperature to more than 1300ºC, which causes the metals to form a molten flux into which the graphite dissolves.

The carbon atoms from the graphite move through the flux towards the cooler diamond seed, and crystallise on the surface of the seed, thereby increasing the size of the diamond crystal. This process continues over a period of days and even weeks.

Chemical vapour deposition (CVD) method

CVD is a more recent method for growing diamond crystals at less extreme temperatures within a vacuum chamber (about 900ºC and pressures well below one atmosphere).

Again diamond seeds, in the form of flat diamond seed plates, are placed inside a chamber, which is filled with a gas containing both carbon and hydrogen, such as methane. The temperature is raised and microwaves are used to break down the gas molecules into carbon and hydrogen atoms, which rain down towards the colder diamond seeds. Without the presence of hydrogen atoms, the carbon would form graphite, but the hydrogen prevents this from happening, allowing the carbon atoms to crystallise as diamond. Again, this crystallisation process can take several weeks to complete.

How are lab grown diamonds graded and certified?

Both the HPHT method and CVD method produce rough diamonds, which need to be cut and polished, just as mined diamonds do, in order to produce the beautiful, finished diamonds that we know and love!

Once they have been cut and polished, lab grown diamonds are graded and certified in exactly the same way as mined diamonds, based on the 4Cs of carat, colour, clarity and cut:

• Carat - The heavier the diamond, the higher the carat. One carat is the same as 0.2g and is divided into 100 points. 
• Colour - "White diamonds" are graded on an alphabetic scale from D (colourless) through to Z (light colour). Diamonds with more colour saturation than Z are called fancy coloured diamonds, and are graded from "fancy light" through to "fancy deep".
• Clarity - All diamonds have imperfections, as either inclusions within the crystal or blemishes at their surface. If a trained diamond grader cannot see any imperfections at 10x magnification, the diamond is graded as Flawless (FL). As imperfections become more prominent the clarity grade goes down, through Internally Flawless (IF), to Very Very Slightly included (VVS1 and VVS2), to Very Slightly Included (VS1 and VS2), to Slightly Included (SI1 and SI1) to Included (I1 and I2).
• Cut - This is an assessment of the proportions that a round brilliant cut diamond has been cut to, and the higher the cut grade, the better the light performance of the diamond (i.e. the more it sparkles). The GIA grades cut from Excellent, to Very Good, to Good, to Fair to Poor. The IGI also has an Ideal cut grade which sits above Excellent on the IGI scale. Note that fancy cut diamonds (all shapes other than round brilliant cut) are not graded for cut whether mined or lab grown.

Lab grown diamonds vs mined diamonds

The only real difference between a lab grown diamond and a mined diamond is its origin. They share the same physical, chemical and optical properties, such that even trained gemologists cannot distinguish them without using sophisticated equipment. For this reason, when you purchase a diamond that has been certificated by a reputable authority such as the GIA or IGI, this will confirm for you whether the diamond is a lab grown diamond or a mined diamond.

FAQs

Summary

Whether you're keen to make an ethical and environmentally conscious purchase, or you simply want to pay less for the same high-quality diamond, it is well worth considering lab grown diamonds.

We offer a huge selection of lab grown diamonds in all shapes, sizes and grades, all independently certificated by the GIA or IGI. View our range of lab grown diamonds and please feel free to get in touch if you'd like to talk to one of our diamond experts.