Swiss lab introduces synthetic melee identifier

Basel--The Swiss Gemmological Institute SSEF in Basel has become the latest laboratory to create a machine designed to distinguish lab-grown melee diamonds from mined.

The Automated Diamond Spectral Inspection, or ASDI, machine analyzes large quantities of melee diamonds in a short period of time, the SSEF said.

The patent-pending ASDI can analyze polished round diamonds ranging in size from 1 to 3.8 millimeters in diameter and operates at an average sorting speed of 4,000 stones per hour, according to the SSEF. For each single authenticated diamond, the machine collects 14 high-precision size and proportion measurements in only 18 micro-seconds per stone.

The machine can identify colorless synthetic diamonds, both HPHT and CVD-grown, as well as colorless HPHT-treated diamonds. It only needs one operator to start a series of controls, and then ASDI can run autonomously.

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“The threat of undisclosed synthetic diamonds possibly mixed into batches of melee diamonds is a very serious issue,” said Jean-Pierre Chalain, director of SSEF’s diamond department.

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“As part of SSEF’s mission to protect the jewelry and watch-making industries, the release of ASDI brings a safe, reliable and very efficient industrial solution to the trade. This machine can authenticate melee diamonds of low individual value using high-tech methods at a highly competitive price per stone.”

According to the SSEF, two major Swiss diamond suppliers and two Swiss jewelry and watchmaking companies have ordered the ASDI machine. As of the end of February, the company already had used the device to test approximately 400,000 diamonds that had been submitted for inspection by the Swiss diamond trade.

The ASDI joins De Beers’ Automated Melee Screening Device, which scans stones between one point and 0.20 carats in size and automatically sorts them into bins according to what it detects, and the synthetics detection device introduced by the Gemological Institute of America in January as lab-grown diamond detection devices recently introduced into the trade. 

The GIA’s machine, however, is not specifically designed for melee. It tests diamonds from one point to 10 carats in size and is not automated; someone must place each stone into the machine.