“Looking at the two diamonds by the naked eye it’s impossible to distinguish the difference – it would take sophisticated equipment,” says Kathryn Edison Money, VP, strategy and merchandising at Brilliant Earth, a diamond retailer selling both lab-grown and mined diamonds.

Cultured diamonds, as they are also known, look the same as natural diamonds because gemologically they are identical. Both are made exclusively of carbon therefore are chemically, optically and physically equal. Only price and origin differ.

Brilliant Earth sells lab diamonds at prices ranging from $375 to $110,000, depending on size, cut and quality, and ethically mined diamonds starting at $500 to $2m.

The cheaper cost is what attracts both millennials seeking a bargain and fraudsters hoping to upsell synthetic diamonds as natural ones.

Unlike natural diamonds formed under tremendous heat and pressure deep within the earth billions of years ago then excavated, cultured diamonds are produced in a laboratory over several days or weeks.

Lab diamonds were first created in the 1950s, with production of larger crystals suitable for jewellery emerging in the mid-1990s. High-pressure, high-temperature (HPHT) and chemical vapour disposition (CVD) are the most popular techniques. As these processes have advanced the production cost of synthetic diamonds has fallen.

Some synthetic diamonds may display visual features such as inclusions, fluorescence reactions and growth features easily identified by a microscope, but many need testing with advanced scientific equipment making them harder to differentiate.

“Some synthetic manufacturers use treatments to obscure these distinctive characteristics, so sophisticated tests are required,” says Russell Shor, senior industry analyst at the Gemological Institute of America (GIA).

Synthetic or natural?

Currently, cultured diamonds dominate the industrial sector, constituting 99% of the market, while in the quality gem business they account for only a small percentage. However, diamonds miners feel that misrepresented synthetic diamonds are threatening the integrity of their operations.

“Undisclosed HPHT synthetics are the focus of our industry’s attention now,” says Lynette A J Gould, head of media relations at The De Beers Group of Companies.

“The entire sector recognises how important consumer confidence is to diamond sales, so there is a zero-tolerance approach. However, there is no doubt about rising concerns around undisclosed synthetics entering the diamond pipeline.” 

"However, there is no doubt about rising concerns around undisclosed synthetics entering the diamond pipeline."

She highlights that trading in misrepresented or undisclosed products, inadvertently or not, could cause irreparable damage to a company’s reputation and would be viewed as fraudulent.

“Purchases from secondary sources, not the polisher of the diamonds, for example, could increase the opportunity for synthetics to be substituted for natural diamonds or spread across parcels sold to unsuspecting customers,” says Gould.

Partner at global consultancy firm Bain & Co, Olya Linde, says unrevealed mixing of cultured diamonds with natural stones is very “difficult to quantify”.

“The problem arises when lab-grown diamonds are misrepresented and sold as natural diamonds, especially in melee categories,” she explains.

Melee is a quarter carat diamond. Due to their small size they are not sent to a certified lab for grading, as with most diamonds over one third of a carat; therefore, cultured diamonds can easily infiltrate a batch of melee diamonds.

Screening is the only defence.

Fighting technology with technology

“GIA’s laboratory and research are a defence against the minority who do not disclose the nature of their product,” says Shor.

Last year the GIA launched a Melee Analysis Service testing diamonds in this category.

In September, De Beers launched a new instrument called the PhosView; a self-contained screening device that can analyse parcels of polished diamonds to determine if they contain potential HPHT synthetics.

Any diamonds identified as possible synthetics can be sorted and sent for further testing by De Beers’ Institute of International Diamond Grading & Research centre. The machine does not screen CVD synthetics, simulants or treated stones.

During analysis, colourless and near-colourless stones in the 0.003ct, one third of a point, or 0.9mm, to one carat size range are viewed on a screen while being subjected to UV light.

The machine is designed to screen loose diamonds as well some jewellery pieces. 

Other devices used for synthetic detection include the ALROSA Diamond inspector, M-Screen by HRD Antwerp, and the AMD device also by De Beers.

"As leaders of the diamond industry we all have a responsibility… to protect ourselves from fraudulent activity, and protect the value of our finite natural resource."

Gould says there are various testing and screening services being adopted and gem labs are testing for cultured diamonds when grading stones.  

“As leaders of the diamond industry we all have a responsibility to our customers, our employees, our partners and, ultimately, consumers to protect ourselves from fraudulent activity, and protect the value of our finite natural resource,” she adds.

Furthermore, the International Organization for Standardization issued a new standard defining nomenclature to be used in the buying and selling of natural and lab-grown diamonds.

However, most available detection devices are expensive – the PhosView costs $4,500. This is unaffordable for smaller diamond and jewellery dealers who are likely not buying direct from the polisher, but a middleman, generating a weak spot for synthetic diamonds entering the market.

Market battleground  

The mined diamond industry is right to be cautious, but it will not know if its efforts are paying off until it collectively quantifies the amount of synthetic diamonds being labelled as natural ones. Presently there is not database to record what is being uncovered.

For legitimate sales of diamonds, organics still dominate.  

Synthetic diamonds are marginally growing in popularity, says Money, especially with millennials who want a cheaper alternative to diamonds.

“Lab Diamonds are resonating quite well with millennials because they are beautiful, affordable and responsible,” she says.

But the experts agree natural diamonds will not lose their charm over cultivated ones for most consumers.

I do not think the mined diamond industry should be concerned,” says Shor, “To purchase a synthetic or organic diamond is down to the preference of the consumer, but I do not see demand for natural diamonds decreasing significantly any time soon.”

Linde agrees.  Although the production costs for lab-grown diamonds continue to decrease as the technology improves, it would still take significant capital investment to grow production to much larger volumes, she says.

“While there are many challenges the diamond industry face that are similar to other luxury goods, the sole most important one is sustaining the long-term demand growth for diamond jewellery, especially among the new generations of consumers,” she adds.

“So long as that diamond dream is alive and well and continues to find its way into the hearts and purses of the new consumers, everything else can be overcome.”