Editors

Why the GIA Grades Lab-Grown Diamonds Like It Does

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.”
Michelle Graffis the editor-in-chief at National Jeweler, directing the publication’s coverage both online and in print.

The Latest

IndependentsMay 17, 2021
Take a Peek Inside the New Zadok Jewelers Store

The Houston jeweler recently opened a 28,000-square-foot, two-level store.

IndependentsMay 17, 2021
Bill Boyajian Has a New Book Coming Out

“Family Business Succession Planning” covers the dynamics of working in a multigenerational business and prepping for the next generation.

MajorsMay 17, 2021
Pandora’s Head of North America Steps Down

Sid Keswani has left the jewelry company to become president of lifestyle company Centric Brands.

Brought to you by
How to Engage and Sell to Millennials

Millennials were once feared in the diamond industry, but now this younger generation has become today’s largest diamond buying demographic.

TechnologyMay 17, 2021
JCK Launches Online B2B Jewelry Marketplace

“Jewelers Source by JCK” will help qualified buyers find new clients and conduct virtual meetings all year round.

Weekly QuizMay 14, 2021
This Week's Quiz
Test your knowledge of jewelry news from the week of May 10-14, 2021.
Take the Quiz
MajorsMay 17, 2021
Borsheims Promotes 3 on Sales Management Team

It shows the Nebraska jeweler’s new cross-department emphasis.

Policies & IssuesMay 14, 2021
Petra Reaches $6M Settlement Amid Claims of Human Rights Abuses

A report by a nonprofit documented an alleged seven deaths and 41 assaults on artisanal miners at the Williamson mine in Tanzania.

Brought to you by
A New Golden Age

Gold has had its share of ups and downs over the last 5 decades. Here’s why the metal is having another big comeback.

AuctionsMay 14, 2021
Phillips’ New Selling Exhibition Celebrates Female Designers

It features pieces from the likes of Solange Azagury-Partridge, Suzanne Belperron, Marina B, and Silvia Furmanovich.

×