Version 2.0 of the NDC’s ‘Assure’ Directory Is Now Live
Assure is the program the Natural Diamond Council launched in 2019 to test lab-grown diamond screening devices.

Assure is the program NDC launched in 2019 to test and analyze the performance of as many diamond verification instruments—devices designed to tell the difference between natural and lab-grown diamonds, as well as diamond simulants—on the market as possible.
Underwriters Laboratories (UL) in Canton, Massachusetts, and the University of Antwerp in Belgium perform the testing.
NDC said this second round of the program and its updated directory show the results of testing the machines on an updated sample of natural diamonds, lab-grown diamonds, and diamond simulants in a range of sizes.
The sample is curated to reflect goods currently in the market, as well as “individual stones that anticipate future trends and pose some of the greatest challenges,” NDC said.
“It would be no good to test these machines using synthetic stones that are known to be easier to identify,” explained Grant Mobley, NDC’s jewelry and watch editor. “We need to make sure these machines work under the most difficult scenarios possible with the most difficult-to-identify stones as possible, as well as the most common types of synthetics on the market.
“In order to do this, we work with gem labs to secure the most common types of stones as well as stones they have identified as more difficult to identify. These more difficult stones are usually very rare on the market, some developed specifically to try to ‘fool’ the machines, but we want to make sure the machines can test them regardless.”
The second version of the program also tests diamonds already set into jewelry, whether in an open- or closed-back mounting.
Currently, there are only three lab-grown diamond screening devices listed in the Assure 2.0 directory: De Beers Group’s DiamondSure and SynthDetect, and M-Screen Ultra from HRD Antwerp.
Mobley said “many more” will be added in the coming weeks as manufacturers submit their newest machines to test.
He also noted the Assure program is ongoing, so as new machines come to market, NDC will work with the manufacturer to try to get them in for testing.
NDC said this updated version of the online directory has improved search filters to allow users to more easily find instruments based on their needs: types of diamonds used, volumes of diamonds processed, size of device, level of expertise required, etc.
The new portal also provides more details on the Assure 2.0 program as well as information on how to protect the integrity of the diamond pipeline.
Previously published test results will still be available via the Assure 1.0 directory.
Manufacturers of diamond verification instruments can now submit to the program both new and existing instruments whose Assure verification is about to expire. (Companies that submit machines for testing receive an “Assure Tested” sticker to place on their instruments. The results, and the sticker, are good for two years. After that, the machine must be resubmitted for testing to still claim to be “Assure Tested.”)
For more information or questions, email assure@naturaldiamonds.com.
The Latest

Executive Chairman Richard Baker will take over the role as rumors swirl that a bankruptcy filing is imminent for the troubled retailer.

Mohr had just retired in June after more than two decades as Couture’s retailer liaison.

Shekhar Shah of Real Gems Inc. will serve as president of the Indian Diamond & Colorstone Association in 2026.

How Jewelers of America’s 20 Under 40 are leading to ensure a brighter future for the jewelry industry.

This year’s good luck charm features the mythical horse Pegasus, and is our first Piece of the Week of the new year.


Articles about crime, engagement rings, and a necklace worn in the World Series generated the most interest among readers.

As part of the leadership transition, Sherry Smith will take on the role of vice president of coaching strategy and development.

Roseco’s 704-page catalog showcases new lab-grown diamonds, findings, tools & more—available in print or interactive digital editions.

It marks the third time the country has headed the Kimberley Process. Ghana will serve as vice chair.

The new Bulova x Stetson designs highlight two animals often associated with the American West—the bison and the Texas Longhorn.

Its residency at Yamron Jewelers will run through May 2026.

From influential executives to innovative designers, we pay tribute to the people we said goodbye to this year.

The retailer is expanding into areas with large Indian and South Asian populations.

The Italian brand has opened its first flagship amid the peaks of the Dolomites in Madonna di Campiglio, Italy.

The new curation at the Natural History Museum of Los Angeles County showcases rare gem and mineral specimens in their uncut, natural state.

The couple pleaded guilty to concealing at least $127 million in cash transactions at its precious metals businesses.

Consumers shared concerns about prices, inflation, tariffs, trade, and politics in the survey’s write-in response section.

In February 2026, the auction house will move its headquarters to the former Steinway Hall, a neoclassical landmark on Billionaires’ Row.

The new show will take place Jan. 23-25, 2026.

The former BHP Billiton leader and Gemfields chairman is remembered for his influential leadership throughout his 50-year mining career.

The LVMH-owned brand has partnered with the costume design union to revamp its award for 2026.

The luxury titan inked a deal to acquire an initial minority stake in the jewelry manufacturer with a pathway to full ownership by 2032.

The company’s curation of unsigned vintage and estate jewelry debuted at the Bloomingdale’s in Costa Mesa, California.

In the recent multi-shipment seizure, CBP also found counterfeit Audemars Piguet, Moncler, and Chrome Hearts items.

Helzberg’s Chief Retail Officer Mitch Maggart shared details about its tests of a new store concept rooted in an elevated luxury experience.

Jewelers of America execs and National Jeweler editors discuss tariffs, the sky-high gold price, and the engagement that broke the internet.

The luxury goods company said founder Ippolita Rostagno will remain at the brand’s helm.




















