The ASDI-500 is able to detect and extract synthetics and simulants as small as half a millimetre in diameter, at the astounding speed of 700 stones per hour.

In 2020, to fill the gap between 0.50 and 0.85 mm, SSEF validated a robust analytical solution based on several thousand manual tests on diamonds as small as 0.45 mm. Later, the Swiss Innovation Agency partly financed the computer processing of ASDI-500 analytical data. In November 2022, the ASDI-500 was unveiled at the international GemGenève show.



The ASDI-500 instrument is now being brought to the market to test melee diamonds with diameters down to 0.50 mm or 500 microns, hence its name ASDI-500. First automatised authentication solution for melee smaller than 0.85 mm.


A batch of stones submitted to the ASDI-500 shall be made of colourless (D to J) round polished (full cut, 8/8, 6/16) stones. The maximum diameter divergence in one batch is approximately 0.15 mm (e.g. 0.60 mm to 0.75 mm). ASDI-500 can automatically inspect batches of melee as small as 0.50 mm up to batches of melee as large 3.80 mm.

Feeding a batch of melee for inspection

An operator pours a large batch of colourless melees – several thousand – into a vibrating hopper. On the touch screen, the operator enters customisable references (e.g. batch reference, total weight, etc.) and just clicks on “START”.

Diamond inspection

Prior to starting inspection, the ASDI-500 runs a fast – less than one minute – automated internal calibration on a diamond of reference included inside the device. This calibration is usually performed once a day and can be launched on demand at any time by the operator. As soon as the calibration is performed the automated inspection starts.

Result of the inspection

The ASDI-500 counts accurately and places au-tomatically all tested stones in one of the following bins:

1) “Natural Diamond”, 2)“Refer”, 3) “Simulant”, 4) “Not analysed”

Result ouput

At the end of the process, the operator can export an inspection result file.

For more information on ASDI-500, pricing and contact details please contact UNIMEC SA.