De Beers launches high-volume melee testing

GradingMar 28, 2016

De Beers launches high-volume melee testing

De Beers now is using its automated melee screener at its International Institute of Diamond Grading & Research facility in Surat, and plans to launch the service at the IIDGR lab in Antwerp next month.


De Beers has begun using its new automated melee screening device at its International Institute of Diamond Grading & Research facility in Surat, and plans to begin offering the same at the IIDGR lab in Antwerp next month.

The International Institute of Diamond Grading&Research, or IIDGR, developed this automated melee tester in order to sort lab-grown diamonds from mined ones. The machine screens 500 carats at a time of colorless, or near-colorless, diamonds between one point and 0.20 carats in size to weed out lab-grown melee from mined.

The device automatically feeds the stones, table-down, into a testing station. After testing, the diamonds are dispensed into one of five bins: pass, refer (more testing is needed), refer Type II (more testing needed, higher likelihood of being synthetic), non-diamond (simulant) or purge (for diamonds that were erroneously loaded into the machine).

They then are returned in a sealed IIDGR package that De Beers said is tamper-proof.

The potential mixing of less-expensive lab-grown diamonds with natural, or mined, diamonds is of growing concern in the industry as diamond growers up production levels and improve quality. Melee is particularly problematic because it often slips through the supply chain untested due to the fact that there aren’t many cost-effective and efficient ways of checking these tiny stones.

In order to combat the problem, De Beers introduced an automated melee screener in January 2014, shortly after the Gemological Institute of America unveiled the DiamondCheck, which also can separate lab-grown melee from mined, starting with diamonds that are as small as one point.

De Beers initially said it would be leasing out the devices to sightholders beginning in the second quarter 2014 and installing multiple machines at the IIDGR in Antwerp later that same year. (The IIDGR in Surat was not yet open at that time.)

David Johnson, a De Beers spokesperson, said that total of five pre-production prototype automated melee screening devices have been in use in Antwerp for two years, as the IIDGR has been testing their durability and accuracy.

The beginning of the service this week marks the transition from testing to widespread use mode for the machine, which IIDGR President Jonathan Kendall said in a statement will “play an important role in supporting both trade and consumer confidence.”

“Sellers will be able to provide potential buyers with pre-checked goods in sealed IIDGR packages, removing any potential concerns around disclosure,” he said.

De Beers began using the automated melee screener, along with other proprietary instruments, at the IIDGR lab in Surat on Wednesday. The facility has a room specifically designed for melee testing.

Melee testing is set to begin Nov. 12 at the IIDGR lab in Antwerp, which also has a room outfitted specifically for melee.

The service will be offered at an introductory discount of 50 percent off in both India and Belgium through the end of the year. For more information, email or visit

As for sightholders, De Beers ended up selling, not leasing, them the automated melee screeners.

Large manufacturers including Kiran Gems, Tasaki, Rosy Blue and Stuller have acquired the devices, playing $55,000 plus a three-year support and maintenance charge of $10,000 a year.

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

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