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

Recorded WebinarsMay 07, 2021
Watch: The Office Called, It Wants You Back

As more people prepare to return to work, two JVC attorneys discuss vaccines, health screenings, permanent remote work, and more.

Events & AwardsMay 07, 2021
Here’s the Latest on Health, Safety Measures for JCK Las Vegas

They include temperature screenings, a “no handshakes, no hugs” policy, and more.

CollectionsMay 07, 2021
Muzo Colombian Emeralds Debuts E-Commerce, New Collection

It’s the famed emerald miner’s first entirely shoppable website.

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.

IndependentsMay 07, 2021
JA Promotes Fine Jewelry for Mother’s Day

The trade organization showcased members’ jewelry on more than 30 morning shows across the U.S.

Weekly QuizApr 29, 2021
This Week's Quiz
Test your knowledge of jewelry news from the week of May 3-7, 2021.
Take the Quiz
TrendsMay 07, 2021
Piece of the Week: Brent Neale’s Emerald Knot Ring

It pairs May’s birthstone with bright turquoise.

Policies & IssuesMay 06, 2021
US Economy Could See Fastest Growth Since the ‘80s

The National Retail Federation expects it to grow nearly 7 percent in 2021 as businesses reopen and consumer confidence continues to rise.

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.

IndependentsMay 06, 2021
Harris Jewelry Closes All Locations

The jeweler will continue to operate online and via phone.

×