GIA Examines Largest Known Diamond Grown Using CVD
It is more than 16 carats and G color/VVS2 clarity as grown, which is unusual in CVD diamonds.

The lab said Tuesday that the diamond is a 16.41-carat princess-cut stone grown by Shanghai Zhengshi Technology Co. Ltd.
The diamond had the “observable characteristics” of diamonds grown using the CVD process, including strong graining throughout—common in CVD stones—that gives the diamond a “wavy” appearance, as visible in the video below.
The diamond is G color and VVS2 clarity. GIA confirmed through detailed spectroscopic readings it was not treated post-growth to improve its color, which is unusual.
GIA Vice President of Research and Development Dr. Wuyi Wang, who examined the diamond, noted, “We have seen very few CVD diamonds of this quality.”
The 16.41-carat stone breaks the previous record for largest CVD diamond—a 14.60-carat emerald-cut stone produced in India and reported on by the International Gemological Institute in August 2021—by nearly two carats.
And it tops the record-holder before that, a 12.75-carat round brilliant lab-grown diamond, by almost four carats.
In article on the 16.41-carat lab-grown diamond authored by Wang and GIA research associates Stephanie Persaud and Elina Myagkay, the authors noted how the technology behind both CVD and high-pressure, high-temperature growth processes for diamonds has advanced significantly in the last two decades.
Wang noted in a GIA news release that he first examined a CVD diamond back in 2003, and it was less than half a carat, pear shaped and brown.
“This 16.41-carat laboratory-grown diamond demonstrates the advances in CVD growth technology. This achievement has important implications for the many scientific and industrial applications for high-quality laboratory-grown diamonds,” he said.
The article is available on the GIA’s website. It also will be published in an upcoming issue of Gems & Gemology, GIA’s quarterly research journal.
Another lab-grown diamond record was set recently, this one for a rough stone that was examined by IGI.
The lab said Jan. 20 that it recently analyzed a 150.42-carat blue diamond grown by biotech company Meylor Global using the HPHT method.
It is the heaviest rough lab-grown diamond on record, breaking the previous benchmark of 115 carats, also set by Meylor Global in September 2020.
The record for a faceted and colorless/near-colorless HPHT-grown diamond is 15.32 carats, tested by GIA in 2018.
The 150-carat diamond is gem-quality, IGI and Meylor confirmed, but Meylor hasn’t decided what it will do with the diamond.
IGI also noted that it recently examined another large lab-grown diamond from Meylor, this one a gray diamond weighing 141.58 carats.

Like GIA, IGI noted that the technology used to grow diamonds continues to improve.
“The acceleration of technology in the lab-grown diamond sector is significant,” said John Pollard, IGI’s recently appointed director of education.
“In addition to record-setting weights, they’re type IIb crystals, a semiconducting category associated with diamond-based electronics. At IGI, we’re seeing new benchmarks from the world’s most advanced producers in jewelry applications and beyond.”
The Latest

The company plans to raise the prices of select watches to offset the impact of tariffs.

Between tariffs and the sky-high cost of gold, designers enter this year’s Las Vegas shows with a lot of questions and few answers.

Designed by founder Renato and his daughter Serena Cipullo, it showcases a flame motif representing unity and the power of gathering.

More shoppers are walking out without buying. Here’s how smart jewelers can bring them back—and the tool they need to do it right.

However, the tariffs remain in effect in the short term, as an appeals court has stayed the U.S. Court of International Trade’s decision.


The pop icon is one step closer to launching her “B Tiny” jewelry collection, a collection she first began posting about last fall.

Sponsored by Stuller

Gain access to the most exclusive and coveted antique pieces from trusted dealers during Las Vegas Jewelry Week.

It was featured in the miner’s latest sale, which brought in $24.8 million.

GemText AI uses artificial intelligence to generate tailored product titles, descriptions, and tags with jewelry-specific language.

The 3,300-square foot location is the jeweler's largest store in North America.

Aging and with myriad health issues, none will serve time for their roles in robbing the billionaire celebrity at gunpoint in 2016.

The WNBA team received rings imbued with meaning, from leaf motifs and its Liberty torch to the number of diamonds used.

A longtime executive at RDI Diamonds, Rickard has served on the JBT board for the past five years.

The two organizations have signed an affiliation agreement that’s expected to be finalized in the coming weeks.

The platinum and diamond watch is part of Sotheby’s upcoming Important Watches sale.

Recovered in Mozambique, “The Kat Florence Lumina” was part of Bonhams’ Hong Kong jewelry auction held last week.

Get a taste of the delicious candy-like gemstones in this Amanda’s Style File.

JSA’s Scott Guginsky provided a list of nine security measures jewelers should observe while locking up for the long weekend.

From Lau’s “Love of a Kind” series, the engagement ring was inspired by the moon and holds a different meaning depending on how it is worn.

The lab has adjusted the scale it uses for nacre grading.

Sponsored by GCAL by Sarine

David Walton will serve three years’ probation after an incident in a hotel bar led to the death of West Virginia jeweler David Ettinger.

The retailer also provided an update on how the tariffs situation in the U.S. is affecting its business.

The family-owned jeweler in Great Falls, Virginia, will be celebrating its golden jubilee with a year’s worth of events.

The nonprofit elected five judges who will decide the winners of its design competition.

This year’s edition includes articles on the favorite tools of notable designers, evaluating when to outsource production, and more.