Policies & IssuesMay 14, 2025
Here’s What Happened to Pope Francis’ RingBefore Pope Leo XIV was elected, a centuries-old procedure regarding the late pontiff’s ring was followed.
EditorsOct 20, 2016
Why the GIA Grades Lab-Grown Diamonds Like It Does
The GIA’s Tom Moses explains the reasoning behind the more general color and clarity grades the lab assigns to synthetic stones.
The 5.19-carat diamond on the left and the 10.08-carat blue diamond on the right are both lab-grown stones recently examined by the Gemological Institute of America’s laboratory in Hong Kong. (Photo credit: left picture, Terry Leung and Johnny Leung; right picture, Johnny Leung, both courtesy of GIA)
Earlier this week, I wrote a story about two large lab-grown diamonds--one 5.19 carats and the other a 10.08-carat blue--recently examined by the Gemological Institute of America’s laboratory in Hong Kong.
In both articles, I noticed the GIA using the following terminology to refer to the stones’ color and clarity: “J-equivalent color” and “VS2-equivalent clarity” for the white diamond, and color equivalent to “fancy deep blue” for the colored stone.
This terminology, for me at least, raised questions about the GIA’s approach to grading synthetic diamonds.
On Wednesday, the very knowledgeable Tom Moses, the GIA’s executive vice president and chief laboratory and research officer, took some time to explain it to me.
Moses said the GIA has been issuing Synthetic Diamond Grading Reports for about 10 years.
On these reports, the GIA does not give specific color or clarity grades.
Instead, Moses said, it grades lab-grown diamonds in broader terms, calling, for example, stones in the D-E-F range “colorless” and those in the G-H-I range “near colorless.”
For clarity, the lab uses only VVS, VS, SI or I for synthetic diamonds.
Why?
Because, “by their very nature, when they grow these diamonds, they are traditionally nitrogen poor,” Moses said, which is, incidentally, also what makes them Type IIa. In addition, many, though not all, CVD-grown diamonds come out a sort of brown color and then are de-colorized through a treatment process to make them colorless or near colorless.
All this is to say that these stones are not going to have the same range of color (D to Z) as mined diamonds, which is why the GIA chooses to use broader categories in grading them. They are grown to be as clear as possible, too, which is why the GIA also uses broader terms for clarity.
The GIA’s grading system, which was created long before the proliferation of lab-grown stones that we see today, was “developed for normal mine run, which doesn’t change. That’s nature,” Moses noted.
However, when the GIA publishes research articles online--like this one on the 5.19-carat diamond that appeared earlier this month--it uses terms such as “J-equivalent color” and “VS-equivalent clarity” to give readers a clearer picture of the stone.
Moses said despite what some people seem to think, the GIA is not doing this to “punish diamond growers.” Rather, the lab just sees it as the most logical way to describe lab-grown diamonds.
He added that from a consumer perspective, he doesn’t think
there is that much demand for specific color grades for lab-grown diamonds. Rather, they’re just happy to have a ring or a pair of earrings that are real diamonds but for a lower price.
“They’re going to say, ‘It looks nice. They sparkle. They’re the price I want to spend. I’ll take them.’”
(I think this same argument could be made for mined diamonds as well, but that’s another topic for another time.)
Moses said while lab-grown diamond companies do ask the GIA to do it differently, he doesn’t see the GIA altering its system in the near future, especially with the improving diamond-growing technology producing more stones of high color and clarity.
“Our mission is to serve the consumer and provide clear and accurate information,” he said. “Although we listen to the industry, ultimately, we are here to serve the public.”
“Right now, I just don’t see a reason why we would make that change.”
“They’re going to say, ‘It looks nice. They sparkle. They’re the price I want to spend. I’ll take them.’”
(I think this same argument could be made for mined diamonds as well, but that’s another topic for another time.)
Moses said while lab-grown diamond companies do ask the GIA to do it differently, he doesn’t see the GIA altering its system in the near future, especially with the improving diamond-growing technology producing more stones of high color and clarity.
“Our mission is to serve the consumer and provide clear and accurate information,” he said. “Although we listen to the industry, ultimately, we are here to serve the public.”
“Right now, I just don’t see a reason why we would make that change.”
More on Editors
The Latest
AuctionsMay 14, 2025
Custom Rolex Pulled From Sotheby’s SaleThe one-of-a-kind platinum Rolex Cosmograph Daytona was estimated to fetch up to $1.7 million.
Lab-GrownMay 14, 2025
State of Diamonds: What’s Next for Lab-Grown Diamonds?While the product has entrenched itself in the market, retailers and consultants are assessing the next phase of the category’s development.
Brought to you by
Las Vegas Antique Jewelry & Watch Show: Showcasing the Most Collectible Merchandise from Across the GlobeGain access to the most exclusive and coveted antique pieces from trusted dealers during Las Vegas Jewelry Week.
CrimeMay 14, 2025
Seattle Detectives Seek Public’s Help in Tiffany & Co. Robberies The police are trying to identify the man suspected of robbing two Tiffany & Co. locations in the area.
Weekly QuizMay 08, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
MajorsMay 14, 2025
Jeff Corey Elected Chair of JBT Board The well-known Maine jeweler takes over for Brian Fleming and will serve a one-year term.
Policies & IssuesMay 14, 2025
Foundrae Donates $11K to Ethical MetalsmithsThe donation was the result of the brand’s annual Earth Day Ingot event.
Brought to you by
Watch: The Winston Red: GIA Examines the Smithsonian’s Newest AdditionSupplier Spotlight Sponsored by GIA
IndependentsMay 13, 2025
Eiseman Jewels’ Renovated Dallas Store Is Bigger and BetterLocated in NorthPark Center, the revamped store is nearly 2,000 square feet larger and includes the first Tudor boutique in Dallas.
MajorsMay 13, 2025
DCA Announces New Learning Platform, Course UpdatesThe nonprofit has made updates to the content in its beginner and advanced jewelry sales courses.
MajorsMay 13, 2025
BIJC Launches New Education FundBIJC President Malyia McNaughton will shift roles to lead the new foundation, and Elyssa Jenkins-Pérez will succeed her as president.
TrendsMay 13, 2025
State of Jewelry Design: The Top 10 Jewelry Trends of the Past DecadeAs a nod to the theme of JCK Las Vegas 2025, “Decades,” National Jeweler took a look back at the top 10 jewelry trends of the past 10 years.
Lab-GrownMay 12, 2025
Lightbox to Go Dark by Summer, De Beers Says The company plans to halt all consumer-facing activity this summer, while Lightbox factory operations will cease by the end of the year.
Policies & IssuesMay 12, 2025
Tariffs on Chinese Imports Temporarily Slashed as U.S.-China Reach Deal Following weekend negotiations, the tax on Chinese goods imported into the United States will drop by 115 percent for the next 90 days.
Events & AwardsMay 12, 2025
Jewelry By Picasso, Dalí on Display at Florida Art Museum “Artists’ Jewelry: From Cubism to Pop, the Diane Venet Collection” is on view at the Norton Museum of Art through October.
Events & AwardsMay 12, 2025
CASE Awards Now Accepting Entries For 2025The deadline to submit is June 16.
IndependentsMay 09, 2025
Lugano Diamonds CEO Resigns Amid Internal InvestigationMoti Ferder stepped down Wednesday and will not receive any severance pay, parent company Compass Diversified said.
CollectionsMay 09, 2025
Pieces of the Week: Marie Lichtenberg’s Collaborations for Mother’s DayLichtenberg partnered with luxury platform Mytheresa on two designs honoring the connection between mothers and daughters.
SourcingMay 09, 2025
Gemfields Resumes Emerald Mining in ZambiaThe miner announced plans to recommence open-pit mining at Kagem.
CrimeMay 08, 2025
Former NYC Jewelry Store Employee Arrested in 2017 Choking Death of Boss Michel Desalles allegedly murdered Omid Gholian inside World of Gold N Diamond using zip ties and then fled the country.
Supplier BulletinMay 08, 2025
Instappraise Introduces Game-Changing Trifold Appraisal FormatSponsored by Instappraise
FinancialsMay 08, 2025
Brilliant Earth Notes an Uptick in Engagement Ring Sales in Q1CEO Beth Gerstein discussed the company’s bridal bestsellers, the potential impact of tariffs, and the rising price of gold.
IndependentsMay 08, 2025
Margot McKinney Lands in the U.S. With New BoutiqueThe brand’s first independent location outside of Australia has opened in Beverly Hills, California.
IndependentsMay 08, 2025
Verragio Announces New Regional Sales ManagerCathy Marsh will lead the jewelry company’s efforts in the upper Midwest and western United States.
FinancialsMay 07, 2025
Pandora Posts Strong Q1, Plans for TariffsThe company has multiple strategies for dealing with tariffs, though its CEO said moving manufacturing to the U.S. is not one of them.
ColumnistsMay 07, 2025
The Smart Lab: Building a Seasonal Marketing Strategy for Mother’s Day and BeyondConnecting with your customers throughout the year is key to a successful holiday marketing push.
SourcingMay 07, 2025
Gemfields Says Emerald Sales Improved in Latest AuctionIts commercial-quality emerald sale held last month totaled more than $16 million, up from about $11 million in September 2024.
