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Our guide to lab grown diamonds

Lab grown diamond engagement ring

For centuries alchemists have tried, unsuccessfully, to create gold from base metals. It seems that in modern times science has managed to achieve what was once seen as impossible and create diamonds in a laboratory! Natural diamonds are of course one of the wonders of the world, forming under extreme pressure and temperature deep within the earth from carbon that can be billions of years old. In the words of the GIA (Gemmological Institute of America) on campus lab gemmology instructor Brenda Harwick, “When it comes to a natural diamond, we are looking at something that is really a rarity and a treasure from Earth. But man-made diamonds have a place in the market as long as consumers know exactly what it is that they are buying. There are other synthetics out there – such as synthetic ruby, emerald and sapphire – so it’s not something new for the jewellery industry to have a synthetic alternative.” It is important to draw a distinction between manufactured (lab-grown / lab-created) and imitation materials. Lab grown diamonds are diamonds, they are not a substitute material. Thankfully the GIA have established techniques to distinguish lab-grown from natural diamonds, so buyers can be assured of the provenance of their purchase. It is however virtually impossible for even a highly skilled gemmologist to make this distinction without the aid of sophisticated laboratory equipment. Common imitation diamonds include colourless sapphire, colourless zircon, synthetic cubic zirconia and synthetic moissanite. They are more easily distinguished from genuine diamonds (natural or lab-grown) because they do not have the same physical and chemical composition.

A laboratory-grown diamond (left) and a natural diamond (right)
A laboratory-grown diamond (left) and a natural diamond (right) [source:]
Surprisingly man-made diamonds have actually been manufactured for industrial uses since the 1950s and they can be found in a range of products and systems, including telecoms, laser optics and computing. The first small synthetic diamond that could be faceted into a gem was created by General Electric as far back as 1970. Routine, though small scale, manufacturing commenced in the mid-1980s and over time the stones have improved in quality and quantity. Today it is possible to buy nearly any gemstone of almost any cut, colour, clarity or carat in synthetic form and they are typically around 30-40% cheaper than their natural counterparts. Synthetic gemstones, and diamonds in particular, are becoming very popular in China and the Far East, where they are now featuring in most of the collections offered by fine jewellers. As with natural diamonds, synthetic stones can be enhanced by heat, chemical or radiation treatment to produce a more desirable colour, colour saturation or clarity. Whereas natural diamonds can take millions of years to form within the earth’s crust, lab-grown specimens can be produced within a matter of weeks. Commercial production of synthetic diamonds is known to be currently taking place in Russia, USA, Ukraine, UK and China. Whilst the temperatures required for the creation of lab grown and natural diamonds are similar, natural diamonds grow with octahedral (eight) triangular faces, whereas synthetic stones form with both octahedral and cubic (six) square faces, allowing technical analysis to determine one from the other. The techniques employed for the creation of lab grown diamonds are continually evolving and improving and they have received a significant boost from the recent establishment of a dedicated research facility in the UK by the industry heavyweight De Beers, clearly showing their belief in their future development.

Lab grown diamond ring in box

Lab grown diamonds are produced using two main methods:

High Pressure, High Temperature (HPHT)

This process effectively recreates in a laboratory the conditions found when natural diamonds are formed in the earth. The diamonds are formed in a growth chamber, into which a source of carbon is dissolved in a molten metal, through which carbon atoms are passed to a small man-made or synthetic natural diamond seed. This essentially ‘grows’ the diamond from the nucleus seed outwards thousands of times faster than the natural process that occurs in nature.

Chemical Vapor Deposition (CVD)

CVD involves the use of carbon-rich gas (such as methane) being employed to produce a man-made diamond in a vacuum chamber. Under these conditions the molecules of the carbon-rich gas degrade into carbon and hydrogen atoms, which in turn form on diamond seeds resulting in square shaped synthetic diamonds.

Lab-grown diamond jewellery
Lab-grown diamond jewellery offered by Signet [source:]
Both natural and lab grown diamonds can, and mostly do, contain inclusions. In terms of colour, most man-made stones are colourless or near colourless, yellow or yellowish-brown. They can however be found in blue, pink, red, green and orange. Both natural and synthetic can be produced in any cut, although most synthetic stones are produced as round brilliant because this is the most popular shape for buyers. Synthetic stones can be created from Melee (under 0.10 carat) to over 10 carats but the vast majority are between 0.25 and 5.00. The GIA first began to grade synthetic diamonds in 2006 and the reports they produce for lab-grown stones are noticeably distinct from those for natural diamonds. The key difference lies in the fact they assess the colour and clarity by way of a descriptive spectrum, as opposed to the graded system employed for natural stones. For further transparency the GIA laser inscribes the girdle of each and every synthetic stone with its report number along with a statement that it is lab-grown. Any reputable jeweller will state that a diamond is lab-grown at the point of sale so it is important to ask whether the stones are natural or synthetic and check the certificate corresponds with the salesperson’s description. The processes and techniques involved in the production of lab-grown stones are expensive, complicated and time consuming. Consequently, the potential cost savings, although significant, may not be as substantial as some people may expect. As with all nascent technology it is likely that the price will come down over time and we may yet see synthetic diamonds on the market for less than half the price of natural stones. It is clear than synthetic diamonds are growing in popularity and they are certainly here to stay.

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