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.
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
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.
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.
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.
Weekly QuizMay 08, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
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.
Brought to you by
Watch: The Winston Red: GIA Examines the Smithsonian’s Newest AdditionSupplier Spotlight Sponsored by GIA
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.
TechnologyMay 07, 2025
Punchmark’s Latest Podcast Features a Very Special Guest National Jeweler Editor-in-Chief Michelle Graff joined Michael Burpoe to talk tariffs, consumer confidence, and the sky-high price of gold.
AuctionsMay 06, 2025
Harwell Godfrey Reimagines 10-Carat Blue Diamond for Met Gala-Ready BroochDesigner Lauren Harwell Godfrey made the piece as an homage to the 2025 gala’s theme, “Superfine: Tailoring Black Style.”
Events & AwardsMay 06, 2025
Here’s Who Made Jewelers of America’s New ‘20 Under 40’ ListExpanded this year to include suppliers, JA’s 2025 list honors 40 up-and-coming professionals in the jewelry industry.
IndependentsMay 06, 2025
Sissy's Log Cabin Opens New StoreLocated in Fort Smith, it’s the Mid-South jeweler’s first store in Northwest Arkansas.
IndependentsMay 06, 2025
Gunderson’s Jewelers to Be Featured on ‘World’s Greatest’ TV SeriesThe episode about the family-owned jeweler will premiere May 17.
IndependentsMay 05, 2025
Zadok Jewelers Opens Store in AustinThe Houston-based jeweler’s new 11,000-square-foot showroom will include a Rolex boutique.
AuctionsMay 05, 2025
Nancy Astor’s Cartier Tiara Heads to AuctionThe turquoise and diamond tiara hasn’t been on the market since it was purchased by Lord Astor in 1930.
SourcingMay 05, 2025
Crater of Diamonds Yields 4-Carat Brown Diamond“The Duke Diamond” is the largest diamond registered at the Arkansas park so far this year.
TrendsMay 02, 2025
Ring Concierge, Kraft Partner on Mother’s Day Macaroni Necklace The childhood craft of making dried pasta necklaces for Mother’s Day is all grown up as the 14-karat gold “Forever Macaroni” necklace.
CollectionsMay 02, 2025
Piece of the Week: Angely Martinez’s Emerald Promise RingSet with May’s birthstone and featuring an earthworm, this ring is a perfect celebration of spring.
MajorsMay 02, 2025
Stuller’s New Bridal Catalog Is Here“Bridal 2025–2026” includes popular styles and a dedicated section for quick pricing references of lab-grown diamond bridal jewelry.
SourcingMay 01, 2025
Tariffs & Colored Gemstones: Relying on Stock, Considering the Ripple EffectThough currently paused, high tariffs threaten many countries where gemstones are mined. Dealers are taking measures now to prepare.
MajorsMay 01, 2025
Peek Inside David Yurman’s New Miami Flagship StoreLocated in Miami’s Design District, the 4,000-square-foot store is an homage to David and Sybil Yurman’s artistic roots.
TrendsMay 01, 2025
Amanda’s Style File: 20 Pieces of Emerald Jewelry for MayMay babies are lucky indeed, born in a month awash with fresh colors and celebrated with one of the most coveted colored gemstones.
MajorsMay 01, 2025
Jewelers of America Opens Applications for 2025 ScholarshipsThe deadline to apply for the Seymour & Evelyn Holtzman Bench Scholarship is June 12.
SurveysApr 30, 2025
Consumer Confidence Hits Pandemic-Level Low Amid Tariff ConcernsWhat’s really worrying U.S. consumers isn’t the present situation; it’s what the economy is going to look like six months from now.
Events & AwardsApr 30, 2025
Instore Show Debuts New Name, Look, and FocusNow called The Instore Jewelry Show, it will include holiday-focused education, interactive workshops, and a window display contest.
