Diamond Light Return: How Cut, Angles and Facets Control the Way a Diamond Performs

 

A diamond is far more than a beautiful gemstone. It is a precisely engineered optical crystal, and the way it interacts with light is governed by the same fundamental principles that apply to a prism.

When light enters a diamond through one of its facets, it does not simply travel straight through the stone. As it passes from air into diamond, the change in optical density causes the light to refract, or change direction. From there, the internal angles of the diamond determine whether that light continues through the stone, escapes, or is reflected back through the diamond.

This interaction between refraction, reflection and facet geometry is fundamental to a diamond’s brightness, fire and overall visual performance.

The Critical Role of Diamond Angles

The angles within a diamond are critical because light must follow a carefully controlled path through the stone.

When light enters through the table or upper crown facets, it is refracted as it enters the diamond. The light then travels towards the pavilion, the lower portion of the stone. If the pavilion angle is appropriate, the light strikes the pavilion facet at an angle that allows it to be reflected rather than immediately escaping through the bottom of the diamond.

The reflected light is then redirected across the stone towards another pavilion facet, where it can be reflected again. From there, it travels back towards the crown and eventually exits through the upper facets and table, returning light towards the observer.

This process is commonly referred to as light return.

In simple terms, the diamond is acting as a sophisticated optical system. The facets are the surfaces that control the direction of the light, while the angles determine whether the light is retained, reflected and ultimately returned to the viewer.

Refraction and Reflection Working Together

Two optical principles are particularly important.

Refraction occurs when light changes direction as it passes from one material into another, such as from air into diamond.

Reflection occurs when light strikes an internal surface and is redirected rather than passing through it.

The relationship between these two principles is what gives a well-cut diamond its characteristic brightness.

The pavilion is particularly important. If the pavilion is too shallow, light can escape through the bottom of the stone rather than being reflected back towards the crown. If it is too deep, light can also be directed away from the viewer.

The objective is therefore not simply to make a diamond deeper or shallower. The pavilion, crown, table and other facets must work together within appropriate proportional relationships.

Why Proportions Matter

A diamond can contain excellent material and still appear dull if it has been cut with proportions that do not manage light effectively.

A well-proportioned diamond allows a significant amount of the light entering through the crown to be redirected back towards the observer.

This is one of the reasons round brilliant diamonds have become so highly developed from an optical and scientific perspective. Their high degree of symmetry makes it possible to study and define their proportions with considerable precision.

The round brilliant is generally regarded as the most symmetrical of the major diamond shapes, allowing established proportion systems and ideal-cut concepts to be applied more consistently.

One of the historic milestones in the development of ideal-cut theory was Tolkowsky’s 1919 Ideal Cut, developed by Marcel Tolkowsky. His work examined the mathematical relationship between a diamond’s proportions and its ability to return light, helping establish the foundations for modern diamond-cut analysis.

Why Fancy-Cut Diamonds Behave Differently

Fancy shapes introduce a much more complicated optical challenge.

Unlike the round brilliant, many fancy shapes are not symmetrical in all directions. This includes elongated oval, marquise, pear and elongated cushion-cut diamonds.

The length and width of these diamonds can have significantly different proportions. Consequently, the pavilion geometry along the length of the diamond may not behave in exactly the same way as the pavilion geometry across its width.

This can produce differences in light return across different areas of the stone.

For example, an elongated oval may have one optical response along its length and another across its width. The same principle can apply to marquise and pear shapes, where the geometry changes considerably from the centre towards the points.

This is one reason why two diamonds of the same shape, carat weight and colour can look noticeably different when viewed side by side.

The Pavilion Is the Engine Room of Light Return

When examining diamond performance, the pavilion deserves particular attention.

The pavilion facets are responsible for much of the internal reflection that sends light back towards the crown. Their angles determine the path that light takes once it has entered the stone.

In an elongated diamond, achieving consistent light return across the entire stone can be particularly challenging. The cutter must balance the pavilion angles, crown facets, table and overall depth to manage light across different sections of the diamond.

A change in one area can influence another.

This is why diamond cutting is both an art and a science. The cutter is not simply removing material to create a particular outline. They are creating a three-dimensional optical structure in which thousands of possible light paths interact.

Facet Modifications Can Influence Light Return

Modern cutting techniques allow cutters to modify facet arrangements and proportions to improve the visual performance of a diamond.

Changes to facet size, placement, depth and symmetry can influence the way light travels through the stone. In some designs, modifications can help compensate for the optical challenges created by an elongated or unusual shape.

A cutter may adjust the geometry of the stone so that particular areas interact with light more effectively. However, these modifications always involve compromises. Improving light performance in one area can potentially affect another.

The goal is therefore to find the best balance between shape, proportions, symmetry, weight retention and optical performance.

Why Two Diamonds Can Look Completely Different

This explains why carat weight alone is never enough to judge a diamond.

Two diamonds can both weigh one carat, have the same colour and clarity grades, and yet appear very different when placed next to each other.

One may look bright and lively, while the other may appear darker or have areas where light escapes.

The difference can be found in the way each stone has been cut.

The combination of table size, crown angle, pavilion angle, total depth, girdle proportions, facet arrangement and symmetry determines how the diamond interacts with incoming light.

For fancy shapes, the challenge becomes even greater because the optical behaviour can vary across the stone.

Looking Beyond the Sparkle

When you look at a diamond and see flashes of white light, coloured fire and areas of brightness and contrast, you are seeing the result of physics occurring inside the crystal.

The diamond has not simply been polished to look attractive. Its facets have been arranged to control light.

Understanding this is important for both consumers and professionals. A diamond should be evaluated not only by its carat weight, colour and clarity, but also by the quality of its cut and the way its proportions and facets work together.

At the Diamond Certification Laboratory of Australia (DCLA), understanding the relationship between a diamond’s proportions, symmetry and optical behaviour is an important part of professional diamond assessment.

The next time you look into a well-cut diamond, remember what is happening beneath the surface: light enters, changes direction, travels through carefully calculated angles, reflects from pavilion facets and is redirected back towards you.

That journey of light is what creates the life and brilliance we see in a diamond.

From rare treasure to 'never-ending supply': What happened to diamonds?

 

The price of diamonds has plunged and supply has surged, disrupting one of the world’s most enduring marketing stories.

Once upon a time, a diamond engagement ring was a powerful symbol of social status: the bigger the rock, the greater its cachet.

Today, ring owners posting in social media forums will often voice a different sentiment: “Does this look too big?”

The diamond industry has undergone an unprecedented shake-up in recent years due to the exploding popularity of lab-grown gems.

The price of a one-carat natural diamond has more than halved since the start of 2022, according to US industry data.

Last month, De Beers — the company that helped define the diamond industry and monopolised it for decades — suspended production at South Africa’s biggest diamond mine, citing a need to cut costs amid challenging market conditions.

It’s the latest sign that the once-booming industry is at a crossroads as collapsing diamond prices force mining behemoths to close mines, delay new projects and suspend production.

At the heart of the upheaval is a physically identical product that has upended one of the most successful luxury marketing stories ever told.

Lab-grown diamonds are real diamonds — chemically and visually identical to those found deep underground.

But rather than forming inside the Earth over a billion years or more, lab gems are created by scientists using one of two primary methods — High Pressure High Temperature (HPHT) or Chemical Vapour Deposition (CVD) — to recreate the conditions under which carbon crystallises into diamond.

It takes a matter of weeks.

How did the story of a gem forged over billions of years, and sold for generations as a symbol of rarity and exclusivity, change so dramatically in just a decade?

A history of diamond-making

After years of experimentation, the first proven human-made diamonds were created in the 1950s.

At the time, there was little concern that they could become serious competition for natural diamonds.

The early synthetic stones were small, brown and of poor quality for use in jewellery, instead used for industrial purposes such as manufacturing.

It wasn’t until the 1970s that General Electric, the American company that pioneered synthetic diamond technology, produced the first gem-quality lab diamonds.

But the technology was still too expensive to make lab diamonds commercially viable for jewellery, and the stones weren’t graded highly under gem colour and clarity standards.

A ‘diamond seed’ is a tiny, microscopic slice of diamond.

As the technology continued to improve, a turning point arrived in 2007: the Gemological Institute of America (GIA), the world’s leading independent authority on gem-grade diamonds, officially recognised lab diamonds.

The GIA began issuing reports for lab gems that year, but they represented only a tiny fraction of diamonds submitted for grading — around 0.05 per cent.

A decade later, lab-grown diamonds still only accounted for a small share of the global market.

But in the last few years, they’ve erupted into the mainstream.

Paul Zimnisky, a leading independent diamond industry analyst based in New York City, says the influx of lab gems has dramatically altered the global market.

“The technology to make those diamonds has rapidly improved, and the price to make them has come down substantially,” Zimnisky tells SBS News.

As the price has come down, that’s when I’ve really seen consumer demand pick up for the man-made diamonds, and that I would say happened within the last five years in a big way.

In 2016, a one-carat natural diamond would retail in the US for around $9,380, while a lab-grown stone of the same cut and clarity would cost $7,820, according to Zimnisky’s data.

Today, the natural diamond retails for $4,900 while the equivalent lab stone can be bought for around $850 or less.

Zimnisky estimates lab-grown stones now account for around a third of the global diamond jewellery market.

Credit: Paul Zimnisky data and analysis

In the US, the world’s largest consumer market for diamonds, six in 10 engaged couples opted for a lab diamond last year, according to annual survey data from wedding planning website The Knot.

That was a 239 per cent increase from the site’s 2020 survey.

At the same time, as lab diamonds are shifting consumer trends, they are also changing global manufacturing and production flows.

With production costs declining, manufacturers in China and India have expanded at an unprecedented scale.

In China, which dominates the global production market, the central province of Henan has become known as the nation’s “diamond capital”. In the city of Zhecheng’s many factories, hundreds of machines work around the clock to produce millions of carats each year.

Today, even experts say they can’t distinguish between a natural or lab-grown diamond without specialised equipment.

“The only way to tell the difference is either through the laser inscription, which is usually engraved on the girdle of the diamond, or through a certificate which is associated with the diamond,” Michael Cohen, managing director of the Diamond Certification Laboratory of Australia, tells SBS News.

“Other than that, you need to put it to a laboratory to actually know the difference. It’s not possible to actually see it visually through a microscope, through basic testing, even your countertop retail test.”

But De Beers has been working to change that.

The London-headquartered multinational has developed a suite of advanced screening machines, costing from around $7,900 to more than $35,000, which allow diamond sellers to distinguish between natural and lab-grown diamonds by analysing microscopic signatures left behind by their different growth processes.

The technology forms part of the company’s broader effort to persuade consumers that a diamond’s origin, rather than its composition, is an important part of its story.

The rise of the big diamond

As larger diamonds have become more affordable and visible on social media, demand for smaller stones of one carat or less has slowed.

Designs that were once reserved for celebrities and the ultra-wealthy are now well within reach for many middle-income earners.

And it’s not just the price that’s more attractive: ethical concerns over the origin of gems have been offset by the lab-grown model, which does not rely on mining or supply chains that pass through conflict zones.

On Reddit forums, it’s now common to see everyday people asking whether a diamond looks “too big” or ostentatious on their finger.

At the same time, some owners of natural diamonds have posted on social media worried that people will assume their ring is lab-grown as large diamonds become increasingly prevalent.

It reflects a generational change in consumer sentiment — one that is fast becoming an identity crisis for the natural diamond industry.

De Beers launched its own lab-grown jewellery brand in 2018 but shuttered it last year to focus on its original product.

It has outlined a plan to invest in emotionally driven campaigns that emphasise the rarity and origin of natural diamonds.

Cohen says the company realised it was giving lab-grown diamonds credibility by selling them under the De Beers banner, but its exit did little to slow demand.

Jana Bowden is a professor of marketing and consumer behaviour at Macquarie University, and says much of the identity crisis faced by major brands stems from the historical emphasis on a diamond’s exclusivity.

“Diamonds have always been seen as an absolute status symbol,” she says.

“So much of this has been driven by the perceived rarity and exclusivity of the diamonds, and of course the controlled supply of diamonds through the market, and particularly De Beers as being the pinnacle brand with the most control of the market and supply.”

From rare to abundant: The ‘forever’ diamond

At its peak in the 1980s, De Beers controlled nearly 90 per cent of the global diamond market.

Its tight control of the world’s diamond supply allowed it to stockpile excess diamonds and manage how many entered the market at any time, helping to keep prices elevated.

Through its marketing, the company famously built the idea that a diamond is rare, “forever”, and the ultimate expression of love, turning diamond engagement rings into a social norm.

It also molded societal expectations around how much an engagement ring should cost.

“Isn’t two months’ salary a small price to pay for something that lasts forever?” a 1980s De Beers ad asked.

Bowden says historic luxury brands like De Beers built lasting perceptions in consumers’ minds.

Really, we’ve been taught and we have learnt how to incorporate diamonds into our lives. This is not something that existed prior to the clever marketing campaigns.

Although diamonds are now far from rare, Bowden says many of those perceptions persist — but the market is splitting in two.

“Interestingly, the legacy branding that’s come from the original, traditional mining of diamonds is also now naturally transferred to lab diamonds as well. So consumers still have that association with exclusivity or a milestone.”

Bowden says the lab-grown diamond market is increasingly appealing to younger consumers, who are often more financially constrained and ethically motivated than older generations.

A three-carat natural diamond (left) and a three-carat lab-grown diamond (right) side by side. Source: Getty / Picture alliance

Ms Elangovan, 33, who asked to omit her first name to protect her privacy, tells SBS News she has accumulated more than 10 lab-grown and natural diamonds in her jewellery collection over the past decade or so.

While she’s fascinated by the history and rarity of a natural diamond, she can no longer justify the price when she can buy a “virtually flawless” lab equivalent at a fraction of the price.

“When I look at it, I’m like, ‘Oh, this existed millions of years before me, and it probably would [for] millions of years after me,” she says of natural diamonds.

“So on that point, labs can’t compete.”

But ultimately, she says she’s thrilled to be living in an age where beautiful jewels are accessible to more people.

“I’m intrigued [that] someone can just recreate millions of years of process in a lab,” she says.

“It’s a fascinating industry. I’m just happy I’m alive now, so I can have really pretty jewellery at a very affordable price and ethically sourced.”

Can the mined diamond industry recover?

The natural diamond industry is now facing headwinds from multiple directions.

Changing consumer spending priorities, skyrocketing operational costs, geopolitical uncertainty, and declining diamond yields have all contributed to mines closing or suspending production in recent years.

Some mines were approaching the end of their lifespan regardless, but plummeting diamond prices and the enormous cost to open new mines have made it harder to justify investment in new projects.

“I think the natural diamond industry has to collect itself and come up with a strategy to further differentiate its product from lab-grown diamonds,” Zimnisky says, adding that the industry must give consumers a compelling reason to pay 10 times as much for a natural stone.

He notes that De Beers is currently up for sale by its parent company, Anglo American, with a potential deal expected this year.

The new owner’s arrival will be “an interesting catalyst” for the industry, he says.

I think they’re probably going to pretty aggressively try to kind of reignite interest and demand and emotional appeal for natural diamonds.

For now, unless prices double or triple over the next decade, Zimnisky doesn’t expect to see significant investment in new mines or the reopening of suspended operations.

Cohen, who has worked in the industry for more than 40 years, says there’ll now be a “never-ending supply” of lab diamonds. But he expects prices may eventually increase as the significant energy required to produce them becomes more expensive — which could potentially create new ethical concerns for consumers.

He believes diamond mining will eventually come to an end, but the market for natural diamonds will endure.

“The biggest supply of diamonds will no longer come from the mine, but it’ll come from the second-hand markets,” he says.

“The diamonds don’t get destroyed. As they say, a diamond is forever.”

Credit sbs.com.au

DCLA to Continue Full Grading of All Diamonds, Including Laboratory-Grown

The Diamond Certification Laboratory of Australia (DCLA) reaffirms its commitment to providing precise and comprehensive grading for all diamonds, including laboratory-grown stones. This approach ensures consistency, transparency, and informed decision-making across the industry.

While the GIA has announced it will introduce a simplified classification system for lab-grown diamonds — using the categories “Premium” and “Standard” — the DCLA will maintain its tradition of detailed grading across the full range of quality characteristics. This includes reporting actual colour, clarity, cut, and carat weight for every diamond submitted, regardless of its origin.

The GIA’s new system, expected later this year, will group lab-grown diamonds based on overall appearance and finish, with certificates including carat and cut details but without specific colour and clarity grades.

DCLA recognises that both natural and laboratory-grown diamonds hold unique value and significance. By continuing to offer full grading reports, the DCLA supports both the trade and consumers in understanding and appreciating the distinct qualities of each stone.

At DCLA, we believe that consumers and the trade deserve full and detailed grading information, regardless of the diamond’s origin. Misrepresentation and confusion are more likely to arise when simplified or vague grading systems are used — especially as laboratory-grown diamonds become more prevalent in the market.

As Australia’s official CIBJO laboratory, DCLA remains dedicated to upholding the highest international standards in diamond certification and grading.

Detecting Lab-Grown Diamonds That Deceive

As Guy Borenstein gears up for Stuller’s Bench Jeweler Workshop in March, there’s one hot topic that will be addressed for the fifth consecutive year: synthetic diamonds.

There’s no shortage of available equipment to detect lab-grown diamonds. According to the Natural Diamond Council (NDC), there are about 40 instruments on the market that aim to discover natural versus synthetic diamonds.

“Five years ago, I asked attendees how many were screening for lab-grown diamonds [LGDs] and one hand went up,” says the director of gemstone procurement for the Lafayette, Louisiana-based manufacturer. That number has grown as the years passed, but “the majority are still not checking,” he adds.

Considering the recent number of undisclosed synthetics sent to labs, retailers should be more vigilant. In the last two months, four labs — comprising one in Italy and three, including the Gemological Institute of America (GIA), with US outposts — have reported incidents of synthetic diamonds submitted for grading under the guise of being natural. The labs, with their multitude of testing instruments and scientific savvy, have the manpower and resources to uncover the truth, but what about retailers, small manufacturers, and dealers? Other than sending every diamond purchased either over the counter or from a jewelry maker to a lab, what can the rest of industry do to guard against unknowing purchases of synthetic diamonds? Screen, baby, screen.

Marc Altman of B&E Jewelers in Southampton, Pennsylvania., started selling synthetics only last year, but has encountered them in newly manufactured goods sold to him as natural and in the engagement rings of unknowing clients. In the case of the new jewelry, he suspects it was an honest error.

“It was one ring,” he says. “It was a big order, and my assumption was that they also made jewelry with LGDs.”

Thanks to his GIA ID100 screening tool, he was able to spot-check trays of new finished jewelry. In the case of individual client rings, he’ll use a polariscope and the ID100 to determine if a diamond is natural or synthetic. In the last three weeks, he’s taken in two rings for resizing that were set with lab-grown and not the natural diamonds that clients thought they had. These examples are why screening goods on intake is critical and reveals deficiencies in disclosure by others at the time of sale. These are lawsuits in the making.

“If I didn’t [screen], my reputation would be at risk,” he says.

Fraud or flub?

Recent high-profile lab incidents aside — like the 6-carat synthetic laser-inscribed as a natural the International Gemological Institute (IGI) examined, or the pink, yellow and brown lab-grown diamonds posing as natural that Gem Science Laboratory (GSI) received — not every facility sees the spike in undisclosed synthetics as deliberate by fraudsters.

As a percentage of all diamonds examined, the number submitted as natural that turn out to be lab-grown is miniscule, says IGI CEO Tehmasp Printer.

“Ten years ago, 95% of parcels were contaminated,” he continues. “Today that number is reduced to half a percent. Initially, some did try to push LGDs as naturals and then labs learned how to ID the material. Now, there are mistakes and errors, but most are not intentional. No manufacturers are polishing LGDs and naturals in the same space; it’s done separately. The problems occur when parcels are given out for memo, and then there is a little switch here and there by mistake.”

Other incidents aren’t as clear. A recent GSI discovery involved mounted brown diamonds with linear graining and polished surfaces “to try to pass it as natural,” maintains Debbie Azar, cofounder and president of GSI. “While initial gemological observations would suggest they were likely natural, our advanced testing processes revealed they were CVD [chemical vapor deposition lab-grown diamonds] almost immediately by looking at their optical defects.”

No matter the intention behind the incidents, GIA takes each one — and steps to avoid them — seriously. For example, nearly every synthetic diamond that comes in for a report is inscribed as such. It also recently unveiled a same-day service for report confirmation of GIA-graded diamonds with or without markings. The service is offered to combat fraudulent inscriptions and for now is free.

“We should all be doing everything possible to ensure consumer trust,” says Pritesh Patel, GIA senior vice president and chief operating officer. Patel is responsible for lab operations. “One is not more vulnerable than another in the trade; everybody should be vigilant,” he cautions.

IGI screening parcel. (IGI)

Identification struggles

One of the toughest tasks in effectively screening jewelry today is the large quantity of small stones. The labs can handle it, but it’s tedious.

“Our biggest challenge is testing items encrusted with micro-pavé — jewelry set with 0.005-carat and smaller diamonds,” says Angelo Palmieri, president of GCAL by Sarine. “The challenge predominantly revolves around exercising patience.”

Then there are the hidden halos of diamonds; only visible diamonds can be easily checked on finished jewelry, so the trade must remember to flip pieces on their sides for inspection.

“We see as many naturals in LGD-set jewelry as we see LGDs in natural diamond jewelry,” adds Palmieri. “We see this happen with everybody, from high-end brands to sightholders. We’re not seeing 50% wrong — we see cases where one is natural or LGD. It doesn’t look intentional; it looks like it’s hard to keep track of the melee.”

Azar, too, is familiar with this wearisome process.

“Pieces with smaller diamonds and melee can be extremely time-consuming and the work is intricate,” she says. “We screen thousands of diamonds each day and we are detecting undisclosed laboratory-grown diamonds every day. They are usually in mounted goods where the mounting obscures full observation of the diamond.”

The solution? Enhanced quality controls such as constant and repeated testing when diamonds are loose and once they’re set. “Most companies don’t want to put in the hard work (and patience) that comes with thorough and complete testing,” observes Palmieri.

IGI screening lab. (IGI)

Tools and techniques

Like Altman, other retailers can use a microscope, polariscope and GIA’s ID100 in store — they’re compact and not too cost prohibitive.

Labs have myriad methods, including custom machines and proprietary research, to uncover the truth. There are also common methods used by all labs, like “Raman and photoluminescence spectroscopy” and “basic gemological testing,” among others, notes Palmieri.

GIA even has a facility in New Jersey devoted solely to the study of lab-grown diamonds to stay ahead of their developments. “GIA spends a tremendous amount on research,” notes Patel.

GIA Gem Instruments Polariscope. (GIA)

Lab consensus is that one instrument isn’t enough. Multiple tools and experienced operators are necessary to reveal undisclosed synthetics.

“Each instrument has its own advantages and limitations,” says Palmieri. “No one machine can give you all the answers.”

Azar urges the trade to adopt a deductive process for distinguishing between naturals and synthetics. For example, does it have garnet crystals? Then it is “definitively natural,” she says. But if a diamond has no inclusions or is type IIa, send it to a lab for testing. For mounted goods, “all bets are off because of the complexities,” she adds.

Dror Yehuda, president of Yehuda Diamond Company — formerly a maker of clarity-enhanced diamonds — shifted to manufacturing diamond detectors around 2015. That’s the year, he maintains, that lab-grown diamonds came to market with gusto. “The vast majority of my customers stopped carrying my Yehuda diamonds and moved to LGDs,” he reveals.

As a result, Yehuda built the first Sherlock Holmes detector, which is in its fourth generation. Three models now exist to accommodate a variety of needs and budgets.

To date, he has sold over 15,000 detectors worldwide.

“The second generation was tested by project Assure and was the only detector other than [De Beers’] SynthDetect that detected 100% of the LGDs,” says Yehuda.

The Assure Directory from the NDC is a resource for anyone trying to determine what instruments to purchase. Assure provides results of independent testing of a “wide range of diamond-verification instruments,” according to Samantha Sibley, technical educator at De Beers Group Ignite in the UK, which spearheads De Beers’ corporate approach to innovation.

Assure tests instruments for “diamond accuracy, referral rates, speed, and natural false positive rates [i.e., does the instrument pass any synthetic diamonds as natural?],” she continues. “The latter is the most crucial measure, and all De Beers verification instruments have a 0% false positive rate from both Assure 1.0 [2019] and Assure 2.0 [2022].”

Big Sherlock. (Yehuda Diamond Company)

Model behavior

Manufacturing house Stuller takes extreme precautions to safeguard against undisclosed synthetics. The firm has 62 pieces of screening equipment and 40 associates to run them. It even has an in-house GIA lab for melee analysis (Stuller staffers aren’t even allowed inside).

Starting at a quarter of a point, Stuller tests every diamond individually, screening more than 5 million units a year. Each stone is tested by at least two different technologies so one “can compensate for the weakness of another,” adds Borenstein. “In a year, 50,000 units out of 5 million go to the lab for further tests.”

The onus is on Stuller to test because of Federal Trade Commission (FTC) regulations.

“Every player throughout the supply chain should test,” he urges. “We are still catching undisclosed stones on a daily basis, so just imagine how many of those are filtering into the market in an area with no screening at all.”

GIA iD100 instrument. (GIA)

Jay Seiler of Jay Seiler Jewelers in Duluth, Minnesota, is a risk taker. He has a Presidium tester to weed out cubic zirconia and moissanite when he buys gold, but no other equipment in-house to test diamonds. Why? He’s a private jeweler now after years of operating a big store. His clients are largely older, known to him, bought diamonds before the advent of lab-grown, and 90% of his work is custom. Still, what about the new diamonds he buys? Therein lies the risk.

By the time someone faces an undisclosed synthetic, however, it’s likely too late. “You won’t be able to defend yourself in court,” says Borenstein.

“Disclosure is not as explicit as it should be, and that will be a huge challenge for retailers in a few years,” says Palmieri.

Source: DCLA

US demand to lift India’s lab-made diamond exports to $8 billion

                       Lab-grown diamonds

India, which cuts or polishes about 90% of the diamonds sold in the world, is ramping up sales of laboratory-made gems as demand from the US surges and they become more accepted in other markets.

Exports of polished lab-grown diamonds may double in the current financial year started April 1 from $1.3 billion in the prior year, Vipul Shah, vice chairman of the Gem & Jewellery Export Promotion Council, said in an interview. “We have a huge potential to grow exports to $7 billion-$8 billion in the next few years on the back of US demand and acceptability in the UK and Australia,” he said.

“It is going to be treated as a fashionable jewelry, which is affordable to the youngsters, and that’s the way the market is going to shift,” Shah said.

Diamonds grown in labs represent a small portion of the market currently — India shipped nearly $24 billion of polished diamonds mined naturally last year. Still, the much cheaper variety has been growing its share as it has the same physical characteristics and chemical makeup as mined stones, with experts needing a machine to distinguish between synthesized and mined gems.

Lab-made diamonds are developed from a carbon seed placed in a microwave chamber and superheated into a glowing plasma ball. The process creates particles that crystallize into diamonds in weeks.

Exports of polished lab-grown diamonds from India jumped about 70% in the April-July period to $622.7 million, while those of cut and polished mined diamonds fell around 3% to $8.2 billion during the same period, GJEPC data showed.

One advantage of the man-made gem is that it has a tracking system that helps monitor the supply chain and maintain consumer confidence in the gems.

“Commercial gem-quality earth-mined diamonds are being replaced completely by lab-grown diamonds,” said Ritesh Shah, director at ALTR, one of the first global lab-grown brands to start business in India. The product’s affordability, low carbon-footprint, size and fine quality offer a big draw for buyers, with the US the front-runner in the shift in consumer behavior, he said.

From a handful of companies growing diamonds in labs in the mid-2000s, there are now about 25 such growers in India, he said. The country contributes about 15% of the global production of lab-grown diamonds, according to the GJEPC.

Source: DCLA