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

She is remembered as an artist who loved her craft and was devoted to her faith, her friends, and her family.

It joins the company’s other manufacturing facilities globally, including in India, Botswana, and Namibia.

The polka dot pattern transcends time and has re-emerged as a trend in jewelry through round-shaped gemstones.

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

Vanessa Hickman, 49, allegedly sold a diamond bracelet that was mistakenly sent to her home.


GIA’s former president and CEO was presented with the Richard T. Liddicoat Award for Distinguished Achievement.

Social media experts spoke about protecting brand reputation through behaving mindfully online.

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

In 2026, the three will come together as “House of Brands,” with Gallet sold in Breitling stores and Universal Genève sold separately.

The second drop, which includes more Elphaba-inspired pieces from additional designers, will continue to benefit nonprofit Dreams of Hope.

Second-generation jeweler Sean Dunn has taken on the role.

Amber Pepper’s main focus will be on digital innovation and engaging younger consumers.

Called “Origin by De Beers Group,” the loose, polished diamonds are being sold in a total of 30 stores in the United States and Canada.

The lariat necklace features a 4.88-carat oval-cut Zambian emerald in 18-karat yellow gold.

A 43-carat sapphire brooch from the Vanderbilt collection was the top lot of the Geneva sale.

Rau is a fourth-generation art and antique dealer from M.S. Rau gallery whose first jewelry collection merges artifacts with modern design.

Former De Beers sustainability leader Purvi Shah will take over the role in February 2026.

La Joux-Perret is based in La Chaux-de-Fonds, Switzerland, and makes solar quartz as well as mechanical watch movements.

She previously taught at Gem-A and is the founder of The Gem Academy.

The British actress and her daughter modeled pieces from the brand’s new “Palette” capsule for its “Once Upon a Time” holiday campaign.

Danny and Gaby Shaftel are now Shaftel Diamonds’ CEO and chief operating officer, respectively.

The jewelry manufacturer’s seasonal offering features its new “Melodie” bangles, as well as mini stud earrings and layering pieces.

With more than 140 activations taking place in New York City now through Nov. 23, these 12 events are can’t-miss moments.

The Chapter 11 filing follows the resignation of CEO Moti Ferder, who stepped down after an investigation into the company’s finances.

The artwork is part of an exhibition featuring works by Kathleen Ryan, an artist known for her gemstone-studded rotting fruit sculptures.

Mark Wall, president and CEO of Canadian mining company Mountain Province Diamonds, will vacate his position next month.

Faustino Alamo Dominguez and his son, 25-year-old Luis Angel Alamo, were gunned down following an armed robbery at their jewelry store.























