GIA CVD synthetic diamond

GIA Recalls Diamonds over Treatment Query

Color grading at the GIA Carlsbad diamond grading lab.

The Gemological Institute of America (GIA) has asked customers to return a number of colored diamonds for reassessment, suspecting that a treatment might have gone under the radar.

The organization will reevaluate certain diamonds with “green or greenish” in the color grade, a spokesperson told Rapaport News last week. The recall applies to reports it issued between January and June 2020. The GIA declined to reveal how many stones were affected or to provide their report numbers.

“Recent research and investigation into potential treatment methods caused us to request the return of the subject diamonds for further analysis,” the spokesperson said.

The institute informed customers about the issue around six weeks ago, and is in the process of collecting and reassessing the diamonds. Some stones could get an “undetermined” ruling, while others may require further testing, the spokesperson explained. Many diamonds had already come back with their natural-color statuses confirmed, market sources said. The GIA bases its conclusions on the “state of knowledge and criteria in place at the date of examination,” it added.

Sources estimated that the number of reports under review was close to 100 and could be much higher. The GIA did not specify the nature of the possible treatment. The case is unrelated to the recent discovery of a treated fancy-color diamond on which the institute reported in the latest edition of its academic journal, Gems & Gemology.

“GIA has been investigating the cause of color in diamonds and other gem materials for nearly 70 years,” the spokesperson continued. “Among GIA’s earliest area of research was determining origin of color of green diamonds, which remains even today one of the most difficult areas of gemology. The research process is dynamic, and we recently discovered new information that may provide new insights about the origin of color of the group of diamonds that we have requested to be returned for review.”

The GIA is already dealing with a wider grading backlog following a rebound in market activity in recent months. The organization is operating with as much capacity as local Covid-19 rules allow, using weekends, second shifts and overtime, the spokesperson said.

Source: Diamonds.net

Diamonds with Fake Inscriptions Turn Up at GIA

The Gemological Institute of America (GIA) has recently received “a number of” lab-grown or treated stones carrying natural-diamond reports and fake inscriptions, the organization warned.

Clients submitted the stones for updated reports or verification services, but the grading documents that came with the goods did not match the stones, the GIA explained Tuesday. The weights and grading scores of the lab-grown and treated diamonds were close but not identical to the original stones that appeared on the reports, and they all featured the corresponding natural-diamond report numbers in the form of counterfeit girdle inscriptions.

In one example, a stone submitted was a 1.51212-carat, D-color, VVS2-clarity, type IIa, lab-grown diamond with a cut grade of “very good.” However, the accompanying report — for which the client was seeking an update — was for a 1.50362-carat, VVS2, E, type I natural diamond with “excellent” cut.

In line with its policy, the GIA overwrote all the fraudulent inscriptions with X’s to obscure them, it added. The organization also issued new reports with the accurate details, and engraved the correct report number onto the girdle, and, where relevant, the phrase “laboratory-grown.” In these cases, it also considers informing the client that submitted the stone, law enforcement, and the public, the GIA noted.

Last month, the institute revealed that it had spotted three synthetic moissanites that clients had submitted with forged girdle inscriptions that disguised them as natural diamonds. The cases at its Johannesburg laboratory were the first times the GIA had discovered fake inscriptions on diamond simulants.

Source: Diamonds.net

GIA Spots Rare Inscription Fraud in Simulant

The Gemological Institute of America (GIA) has uncovered three synthetic moissanites with forged inscriptions that fraudsters had used to misrepresent them as natural diamonds.

The cases at the Johannesburg laboratory marked the first times the GIA had discovered fake girdle inscriptions on diamond simulants, it said in a recent article in its academic journal, Gems & Gemology.

The lab initially received a round brilliant, 1.02-carat stone for a diamond-grading report. The report number on the girdle was for an E-color natural diamond with the same weight that was graded in 2019, but the dimensions were different because moissanite has lower specific gravity, meaning that it weighs less relative to its volume.

Standard testing showed the stone was not a diamond, while subsequent spectroscopic and gemological analysis proved it was synthetic moissanite, GIA researchers wrote in the fall 2020 edition of Gems & Gemology, which it released last week.

“The possibility exists that a consumer could purchase this simulant thinking it was a natural diamond, especially with a deliberately misleading inscription,” wrote Sicebiso Hlatshwayo, a supervisor of diamond grading at the GIA in Johannesburg, and Sally Eaton-Magaña, senior manager of diamond identification at the GIA in Carlsbad, California.

Since writing the article about the first stone, the same lab in South Africa received and identified two more synthetic moissanites with fraudulent inscriptions, the GIA added in a note.

In addition to the size discrepancy, the first stone’s clarity was equivalent to VVS2 (the GIA doesn’t usually give moissanite a grade of this type), whereas the diamond it was impersonating was VVS1. The inscription’s font was also distinctly different from the GIA’s standard one. The GIA obscured the fraudulent inscription, in line with its usual practice.

People sometimes mistake synthetic moissanite for diamond because some of their properties are similar, such as their hardness and thermal conductivity, the gemologists explained. The latter feature is often a method of distinguishing diamonds from simulant, but it can fail if the stone is moissanite.

However, the stone showed “double refraction” — a feature of moissanite, absent in diamonds, that gives it more brilliance.

Another key difference between the materials is dispersion, the GIA pointed out. Moissanite has higher dispersion, meaning light that enters the stone is refracted more. The eye, therefore, sees a more distinct range of colors, giving it more “fire” than diamonds.

Source: Diamonds.net

GIA Unveils New Lab-Grown Reports

The new GIA lab-grown diamond reports. (GIA)

The Gemological Institute of America (GIA) has launched its new grading reports for lab-grown diamonds, offering an updated look and format.

The new documents, branded “LGDR by GIA,” come in digital-only form and use specific color and clarity scores rather than the descriptive terms and ranges that appeared in its previous reports, the organization said Tuesday.

“The evolution of GIA’s reports for laboratory-grown diamonds is fully aligned with our mission to protect all consumers,” said Susan Jacques, GIA president and CEO. “Everyone who purchases gemstone jewelry — whether natural or laboratory-grown — expects and deserves the information, confidence and protection that come with a GIA report.”

The offering includes two different Laboratory-Grown Diamond Reports for colorless synthetic diamonds — a standard report and a dossier — and two for colored diamonds: one with plot diagrams and one without.

Notably, the GIA avoids calling the documents “grading reports” — a term it reserves for natural diamonds. Earlier this week, the World Jewellery Confederation (CIBJO) recommended that laboratories use that term only for natural stones and instead call synthetics reports “Laboratory-Grown Diamond Product Specifications,” arguing that the concept of grading implies rarity.

“The color and clarity specifications for laboratory-grown diamonds are described on the same scale as GIA grading reports for natural diamonds, but that does not correlate to nature’s continuum of rarity,” the GIA noted.

The reports state that a stone was created by chemical vapor deposition (CVD) or High Pressure-High Temperature (HPHT) and that it may include post-growth treatments to change the color. Each report also comes with a QR code linking to a custom page on GIA’s website with information about lab-grown diamonds.

Each stone will also receive a laser inscription with the report number and the words “laboratory-grown,” unless another acceptable term already appears on the girdle.

Source: Diamonds.net

GIA to Give Full Color, Clarity Grades for Lab-Grown

The Gemological Institute of America (GIA) is launching a new digital report for lab-grown diamonds that will feature specific color and clarity grades. The organization, which currently only offers loose descriptions and grade ranges for synthetics, will introduce the new reports early in the fourth quarter, it said Tuesday.

The service will incorporate the GIA’s two existing lab-grown reports. Its full reports — available for stones weighing 0.15 carats and larger — will include a 4Cs assessment and plotted diagrams showing clarity and proportions. Its lower-priced “dossiers,” which are available only for stones ranging from 0.15 to 1.99 carats, will just include the 4Cs assessment and the proportions diagram. The lab will also offer specific color and clarity grades for lab-grown colored diamonds.

The GIA began grading synthetic diamonds in 2007, and has since aligned the service more with what it offers for natural stones. Until last year, it only provided descriptions of color and clarity, such as “colorless” and “slightly included.” However, from July 1, 2019, it started indicating the range of traditional color and clarity scores to which those descriptions referred — such as “D to F” and “SI1 to SI2.”

The institute has now moved a stage further, arguing that enhanced transparency will benefit consumers and the trade.

“Natural- and laboratory-grown diamonds coexist today, accepted by both consumers and the trade,” said CEO Susan Jacques. “Ensuring consumers’ trust with GIA’s reliable, independent and authoritative grading reports for all diamonds benefits the public and the entire gem and jewelry industry. We believe the growth of laboratory-grown diamonds will expand the overall diamond market and bring in new customers.”

The reports will only be available in a digital format and will feature an updated design that distinguishes them from their natural-diamond counterparts. The California-headquartered organization will continue to laser-inscribe the stones with the words “laboratory-grown” alongside the GIA report number to further ensure differentiation from naturals. The documents will still carry a statement that the graded stone may have undergone post-growth treatment to alter its color, the GIA pointed out.

The GIA is keeping the same fee structure as for natural-diamond reports since the grading work is the same, it noted.

Source: Diamonds.net

Five GIA Labs Resume Operations

The Gemological Institute of America (GIA) has reopened laboratories in five locations following COVID-19 shutdowns.

The organization’s labs in Johannesburg and Tokyo recommenced limited operations on May 7, the GIA said Monday. Visitors to the Johannesburg lab must make an appointment, have a permit, and wear a mask. The Tokyo location will accept and return goods by delivery only.

On May 11, the GIA resumed operations at its locations in Antwerp and in Gaborone, Botswana. While Antwerp is receiving customers by appointment only, Gaborone is open with a limited capacity to comply with government mandates and allow for proper social distancing, the GIA noted. The lab in Carlsbad, California, reopened May 18, with submission of goods only accepted by shipment.

Labs in Bangkok, Hong Kong and Ramat Gan, Israel, are all open, and are operating with regular hours. Operations in Mumbai, Surat and New York remain closed.

“Our first priority is to protect the health and safety of all staff, clients and visitors,” said Tom Moses, the GIA’s executive vice president and chief research and laboratory officer. “As we work to meet our clients’ needs whenever and wherever possible, we are planning for the safe opening of all other GIA locations as soon as conditions and government authorities permit.”

Source: Diamonds.net

GIA Spots Natural-Synthetic Hybrid Diamond

The Gemological Institute of America (GIA) has discovered a synthetic layer that improved the weight and color of a natural diamond, and has warned that the phenomenon may be happening more often.

The cushion modified brilliant, 0.64-carat stone contained about 0.10 carats of chemical vapor deposition (CVD) diamond, the GIA estimated in a lab note last week. The lab-grown layer was greyish-blue, in contrast to the natural section’s yellowish color, giving the combined stone a fancy-greyish-greenish-blue appearance.

This was not the first time a stone of this type has turned up at the GIA: In 2017, it reported on a 0.33-carat, fancy-blue diamond that featured a CVD overgrowth similar to this one.

“With the second of these composites seen at GIA, this could be a new type of product entering the market,” research associate Troy Ardon and analytics technician Garrett McElhenny wrote in the note, which the GIA published in the Spring 2019 issue of its quarterly scientific journal, Gems & Gemology. “The resulting color was likely the main motivation for growing the CVD layer on top of the natural diamond, though the extra weight gained could also be a factor.”

The stone’s unusual nature came to light after testing indicated it had features of both type Ia and type IIb diamonds — a rare combination. It appeared to have absorbed both nitrogen — a feature of type Ia diamonds that gives yellow color — and boron, which is present in type IIb stones and can turn them blue. “Mixed-type diamonds always call for additional scrutiny,” Ardon and McElhenny explained.

The pavilion — the section from the girdle to the bottom — showed natural growth features during fluorescence testing with DiamondView, a De Beers machine for identifying synthetics. However, the crown displayed characteristics of CVD, proving that manufacturers had grown CVD diamond over a natural base. Using computer modeling, the research team was able to calculate the weight of the synthetic part as approximately one-tenth of a carat.

The stone was well disguised: Numerous readings of its photoluminescence showed no indication of any synthetic origin, despite the fact that such tests are usually effective at revealing CVD. This may be because the lab-grown layer was so thin, the note pointed out.

“Natural diamonds with synthetic diamond grown on the surface require extra scrutiny due to the presence of natural-looking features, both spectroscopic and gemological,” the authors continued. “Careful inspection still reveals the presence of synthetic indicators, which expose the true nature of the diamond.”

Source: diamonds.net

July, 2017February, 2025

Synthetic Diamond

A synthetic diamond (also known as a lab-grown diamond, man-made diamond, or cultured diamond) is a diamond that is created through artificial processes in a laboratory rather than being formed naturally over millions or billions of years in the Earth’s crust. Despite their man-made origins, synthetic diamonds have the same chemical composition, physical properties, and optical characteristics as natural diamonds, making them a true diamond in every sense. However, the main difference is that they are created in a controlled environment in a much shorter time frame, often just a few days or weeks.

How Synthetic Diamonds Are Made:
There are two primary methods used to produce synthetic diamonds:

High Pressure High Temperature (HPHT): The HPHT method simulates the intense pressure and temperature conditions that occur deep within the Earth, where natural diamonds form. In this process, carbon is subjected to pressures of around 1.5 million psi and temperatures of 1,500°C (2,732°F). The carbon is then placed in a chamber with a metal catalyst, which helps the carbon crystallise into diamond. The HPHT method is often used for producing gem-quality diamonds and is also used to create diamonds for industrial purposes.

Chemical Vapor Deposition (CVD): The CVD method involves using gaseous hydrocarbons (like methane) to create a plasma (an ionised gas) that breaks the bonds of the molecules in the gas, allowing the carbon atoms to slowly deposit layer by layer on a substrate (a small diamond seed). Over time, the carbon atoms arrange themselves into the crystal structure of a diamond. This process is carried out in a vacuum chamber at lower pressures and temperatures compared to HPHT. CVD diamonds can be grown to large sizes and are often used for high-quality gem diamonds as well as industrial applications.

Properties of Synthetic Diamonds:
Chemical Composition: Synthetic diamonds are composed of the same material as natural diamonds: pure carbon. The atoms of carbon are arranged in a specific crystal lattice structure, which gives diamonds their famous hardness and brilliance. Synthetic diamonds are made from high-purity carbon and undergo similar processes of crystallisation, resulting in diamonds with the same chemical bonds and rigid lattice structure as natural diamonds.

Hardness: Synthetic diamonds are just as hard as natural diamonds. They score 10 on the Mohs scale of hardness, the highest possible rating. This makes them incredibly durable and resistant to scratches, just like their natural counterparts.

Appearance: Lab-grown diamonds have the same optical properties as natural diamonds, including their brilliance, fire, and scintillation. This means they will sparkle and shine in the same way when exposed to light. Since they are chemically identical to natural diamonds, their appearance is indistinguishable to the naked eye. Advanced gemological testing is often required to differentiate between natural and synthetic diamonds.

Cost: One of the biggest differences between synthetic diamonds and natural diamonds is their price. Due to the shorter production time and technological advancements in the manufacturing process, synthetic diamonds typically cost significantly less than natural diamonds of the same size and quality. This price difference makes synthetic diamonds an attractive option for those seeking a diamond at a more affordable price point.

Environmental and Ethical Considerations:
Environmental Impact: Synthetic diamonds have a much lower environmental impact compared to natural diamonds. The mining of natural diamonds can be destructive to the environment, involving large-scale operations that disturb ecosystems and generate waste. In contrast, lab-grown diamonds have a much smaller carbon footprint, as they do not require the large-scale excavation of land or the energy-intensive processes associated with diamond mining.

Ethical Sourcing: Synthetic diamonds also offer a more ethical alternative to natural diamonds. The diamond mining industry has faced criticism over the years for issues related to human rights violations, including child labour and exploitation in conflict zones, known as “blood diamonds”. Synthetic diamonds, however, are produced in controlled laboratory settings where workers are paid fairly and the production process is transparent, making them a more ethical choice for those concerned with the origins of their jewellery.

Types of Synthetic Diamonds:
Gem-Quality Synthetic Diamonds: These diamonds are created for use in fine jewellery and have the same quality and appearance as natural diamonds. They can be cut into various shapes, including round, princess, emerald, oval, and more. Gem-quality synthetic diamonds are graded using the same criteria as natural diamonds, such as carat weight, colour, clarity, and cut.

Industrial Synthetic Diamonds: These diamonds are typically smaller, lower-quality diamonds that are used for industrial applications, such as cutting, grinding, and drilling. Industrial synthetic diamonds are produced in larger quantities and are not necessarily intended for use in jewellery. They are valued primarily for their hardness and durability, which makes them ideal for heavy-duty tools and machinery.

Distinguishing Between Synthetic and Natural Diamonds:
While synthetic diamonds are physically identical to natural diamonds, they can still be differentiated using advanced technology:

Inclusions: Synthetic diamonds may contain inclusions that are different from those found in natural diamonds. For example, synthetic diamonds grown using the CVD process often have distinctive inclusions, such as gas bubbles or metallic inclusions, which can be detected by a gemologist.
Growth Patterns: Under microscopic examination, the growth patterns of synthetic diamonds can be identified. HPHT diamonds, for instance, may display distinctive growth patterns in their crystal structure.
Spectroscopic Testing: Laboratory tests, such as infrared spectroscopy or ultraviolet-visible spectroscopy, can be used to determine whether a diamond is synthetic or natural.

Synthetic diamonds offer a cost-effective, ethical, and environmentally friendly alternative to natural diamonds. Created using advanced technology in a laboratory, these diamonds possess the same chemical structure and visual properties as their natural counterparts. Whether for fine jewellery or industrial uses, synthetic diamonds provide an option that caters to a growing market of consumers looking for diamonds at a lower price point, while still enjoying the beauty and durability of this remarkable gemstone.

Gemmological Institute of America seven week graduate diamond diploma

The GIA a gemmological organisation will be conducting a seven week graduate diamond diploma from January 8.

The programme combines theory lessons with practical hands on learning and will be held in Jaipur.

Students will learn how to grade in accordance with the GIA’s 4Cs colour, cut, clarity and carat weight of diamond in the D-Z colour range.

As well as how to grade diamonds and detect simulants and treatments like fracture filled diamonds using gemmological equipment.

The course will be taught by instructors from the Mumbai campus.

Fraudulent GIA Diamond Certificate Found

The Gemological Institute of America (GIA) has identified and seized a bogus diamond grading report appearing recently in Hong Kong.

In a news release issued on Wednesday, GIA revealed that although the number of the diamond grading report was in existence in their database, it corresponded to a higher-quality diamond with different measurements, colour, and clarity. According to GIA, a lower quality diamond was cut to match the specifications of the diamond that went with the original report. Furthermore, GIA stated that upon closer scrutiny of the false diamond grading certificate, it was discovered that there were several characteristics inconsistent with those found on an authentic GIA diamond grading report, including differences in font, colour, and background.

In the same release, GIA revealed that their investigation had tracked the counterfeit diamond certificate back to Antwerp, Belgium, a major diamond trading center. Information on the perpetrators is now being sought by the GIA, who is working law enforcement authorities around the world to help detect and prosecute such criminal activities. GIA asks that any individuals with information about either this particular bogus certificate or any other fraudulent activity bring it to their attention.

To help both the industry and public, all major laboratories provide an online database service that allows individuals to check the authenticity of a diamond certificate online by entering the diamond report number and the carat weight of the diamond, which then pulls up all available information about the diamond.

However, this online verification service only serves to determine if the certificate number exists, not if the diamond that accompanies it matches the certificate. GIA offers a verification service to confirm the authenticity of a diamond grading report whereby clients must submit both the diamond and certificate to the GIA laboratory.

In Australia, DCLA performs this verification service and individuals may bring their diamond and accompanying diamond certificate to the DCLA for verification; please contact the laboratory for more information.