Ethically Created Diamonds

High quality laboratory-grown diamonds look and feel like naturally mined diamonds, are difficult to grow and are rare


  • There are two different methods used to grow laboratory ("lab") diamonds: HPHT (High Pressure High Temperature) and CVD (Chemical Vapour Deposition).

    Also referred to as synthetic or artficial diamonds, laboratory grown diamonds have the same chemical composition, crystal structure and optical properties as a mined diamond.

    Lab grown diamonds are NOT diamond simulants, which are products that imitate the appearance of diamonds without a similar chemical composition.

  • Lab diamonds look and feel like mined diamonds and just like mined diamonds they vary in colour, clarity and weight

  • Lab diamonds represent a more sustainable and environmentally ethical choice

  • Pobjoy lab diamonds are all certified by the IGI or GIA in exactly the same way as natural mined diamonds

  • Lab diamond production involves high cost sophisticated equipment and highly skilled specialists

  • Each IGI and GIA certified lab grown diamond includes the certificate number nano inscribed on the girdle of the diamond

  • Because they are of the same composition as naturally mined diamonds, they pass the same industry standard thermal and electrical testing techniques

  • Lab diamonds are significantly less expensive than mined diamonds especially in the case of higher grade larger carat weights

  • Although the choice of high quality lab diamonds is limited it is steadily increasing

How Do The IGI & GIA Identify A Laboratory Grown Diamond?

Experienced gemologists and jewellers cannot differentiate between a laboratory grown and a atural diamond, even under magnification and with a thermal electric diamond testing device.

So before a diamond is graded - natural or laboratory grown - it is subjected to additional scientific testing.

The preferred process is to use a highly sophisticated fluorescence spectropscopy device.

This equipment is capable of identifying unique - albeit extremely subtle - differences between a laboratory grown and a natural diamond.

These differences are only detectable with the use of this specialised equipment and cannot be identified under ultraviolet light nor extreme magnification.

While this process is wholly effective, advances in laboratory growing techniques require the grading institutes to continuously evolve and adapt such technology to ensure it's efficacy.

The diamond industry and the respected grading institutes which effectively regulate it's activities are committed to ensure a clear and distinct two tier market between natural and laboratory grown diamonds, for the benefit of consumers, producers and retailers alike.

Once a diamond has been tested, categorized and graded by the IGI or GIA these details, including a uniquely allocated identification number, are recorded on the relevant database.

This same information is also detailed in a paper certificate supplied with the diamond to the buyer. Each certificate includes a holograph and micro-print lines to mitigate duplication. The buyer of each diamond is also able to verify it's unique identification number and specifications against the IGI or GIA online database.

The Two Growing Methods

High Pressure High Temperature (HPHT) Method

The HPHT method is the original method of creating lab grown diamonds. Gem quality HPHT diamonds were introduced in the 1950s.

To grow an HPHT diamond, a small diamond seed is placed in carbon, the element that diamonds are made of. The diamond seed is exposed to extreme heat and pressure, replicating the way diamonds are naturally grown underground by the earth.

The diamond seed is exposed to temperatures of over 2,000 degrees fahrenheit and pressure of about 1.5 million PSI (pounds per square inch). The carbon melts and forms a diamond around the seed. It is then cooled and the diamond is formed.

Chemical Vapour Deposition (CVD) Method

The CVD method was created in the 1980s. The CVD method imitates how diamonds form in interstellar gas clouds. The CVD method uses less pressure than the HPHT method as well as smaller machines.

The CVD method places a diamond seed in a vacuum chamber. This chamber becomes filled with carbon rich gases and is heated to nearly 1500 degrees fahrenheit. The gas turns into plasma from these extremely high temperatures, causing the release of carbon pieces. These carbon pieces become layered onto the diamond seed, which grows the diamond.

The CVD process produces Type IIA diamonds, which are extremely rare for naturally occurring diamonds. This can help scientists determine if a diamond is lab grown or earth grown.

Which method is better? Both methods produce visually identical diamonds, assuming identical grading and when advanced filtering is applied in the specific diamond selection process.

Pobjoys will carefully select your diamond from what is currently available in the market, avoiding any blue or yellow hues which can occur in some laboratory grown stones.

Video shows 15 hours of CVD-created rough diamond growth (Carat Systems, MA)

High Quality Laboratory Diamonds Are Difficult To Grow And Are Rare

Just like in the mined diamond industry, there are two completely different supplies of HPHT and CVD laboratory grown diamonds: high quality and low quality. Most of what is on the market is low quality and rarely certified by a recognised grading institute.

Pobjoy Diamonds only source high quality laboratory grown diamonds that comply with the same quality filtering processes we apply to mined diamonds. They are also either IGI or GIA graded and certified.

Diamond Comparison

F/VS1 excellent cut mined diamond

F/VS1 excellent cut laboratory grown diamond

Both diamonds IGI certified 1.20 carat eye-clean

Why Is It Difficult To Grow High Quality Laboratory Diamonds?

There is a well-known speed limit as to how fast a diamond crystal can be grown. If you try to grow a diamond faster, the diamonds will have fractures in the crystal resulting in low-clarity. Hot, fast growth also produces more voids in the crystal structure which results in brown, yellow, and grey undertones.

The cost of cutting and polishing a rough diamond into a diamond gemstone is A) significant and B) exactly the same for both grown and mined diamonds. Diamond is the hardest naturally occurring material on earth, and it can only be cut and polished by other diamonds or multi-million dollar laser tools.

A general lack of knowledge about lab grown diamonds has led to the emergence of numerous "alternative facts". Some examples of these include a limited resale ability of lab diamonds (false), that lab diamonds change colour over time (they don’t), or that lab diamonds actually use more energy than strip mining the earth (they don’t).

Price History & Future Values

The prices of laboratory grown diamonds took an abrupt adjustment lower in 2017 when a well known global mined diamond producer entered the market and strategically forced prices lower.

This led to a near 40% reduction in market prices. Since that time the prices of genuinely high quality certified lab diamonds have essentially been constant. During this same period the market value of mined diamonds has fluctuated with a sharp decline during the early COVID-19 pandemic before recovering in to late 2020.

In 2020 laboratory grown diamonds accounted for less than 10% of global combined diamond demand in carat weight terms.

This represents a steady increase over the past five years and with many people increasingly attracted by what are widely regarded as more ethical production methods and accessible prices, it is likely that demand will continue to grow.

Increased supply is likely to meet this demand shift but it should be noted that premium grade eye-clean laboratory grown diamonds - especially over 1 carat weight - that we supply are not so easily created.

Of course there is no way of predicting the future value of laboratory grown - or mined diamonds for that matter. In any case, we do not recommend buying either type of diamond solely in anticipation of them rising in price, although we hope they do! The focus should be on finding the very best diamond available within your budget and which you truly love.


* Typical surface diameter. Actual sizes vary.

More About Certification

Every laboratory-grown diamond we supply is certified by the International Gemological Institute (IGI) or the Gemological Institute of America (GIA), the benchmarks for laboratory-grown diamond grading.

A different report is issued for synthetic diamonds than for mined diamonds by each grading institute. IGI laboratory reports are yellow or white rather than blue.

GIA reports include a navy blue header rather than beige and white.

Laboratory-grown diamonds present an exciting opportunity for customers to get a bigger diamond at a lower price point.

Call us on +44 (0) 20 3998 3075

Laboratory-grown diamonds are referred to here variously as lab diamonds, laboratory diamonds, synthetic diamonds and artificial diamonds with each term havng the same meaning.


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