Reports for Small Diamonds

Authentication of Small Diamonds

Since 2004, the Swiss Gemmological Institute - SSEF checks the authentication and the quality of colourless melees batches for most of the major Swiss luxury watchmaking manufactories and due to changes in producing synthetic diamonds, the authentication of melee batches has evolved from bulk observations to a stone per stone analysis.

ASDI - Automated Spectral Diamond Inspection is a machine developed by SSEF that now enables the screening of melees at reasonable price. You can find more information about this machine in our most recent Facette (no. 21, 2014) on pages 11-12.


Order Form for small diamond testing (needs to be submitted with stones upon shipment)


A sample ASDI testing report for melee diamonds may be found here in English (PDF) or French (PDF)


Sample ASDI measurements report for melee diamonds are here in English (PDF) or French (PDF)





Quality control of small diamonds

The Swiss Gemmological Institute SSEF has set up a process for the quality control of colourless small diamonds (melees and baguettes), thereby satisfying the demands of the watch- and jewellery industry. Detailed SSEF certificates help our customers to better evaluate the quality of their lots of small diamonds. Our routine ensures the best reproducibility of results and our experience gives our clients trustful results.

We routinely control colour, clarity and quality cut of small diamonds. Each diamond that is subject to quality control is also authenticated using the ASDI machine. Each step is double checked by two independent experts.


  • Each single diamond is placed table down in a white folded paper under a normalised light. 
  • Each single diamond is compared to our CIBJO diamond Masterstones.
  • When checking the colour of a small diamond it is important to compare it to a large diamond masterstone. This reduces colour grading margin errors, as opposed to the comparison with a small diamond masterstone.


  • Sortoscope is used for the purity control of small diamonds and enables the visual control of a large quantity of small diamonds. 
  • The size of an inclusion is measured with a special eyepiece.
  • The final purity grade is defined by means of the 10x loupe.
  • Finally, stones can be compared with SSEF clarity master stones.

Cut (symmetry, polish, proportions)

  • SSEF has created a Symmetry Masterset for small diamonds. This Symmetry Masterset groups more than 30 selected diamonds from an ‘Excellent’ to a ‘Poor’ symmetry grade.
  • For evaluating the symmetry grade of a diamond we check : roundness ; eccentric or tilted or wavy tables, truncated or short facets, facets of unequal size, edge displacement ; girdle with unequal thicknesses, etc. 
  • SSEF has created a Polish Masterset for small diamonds. It groups more than 8 selected diamonds from «Excellent» to «Poor» polish grade.