Glittering Stones » Gemstone Research Centers » Swiss Gemmological Institute (SSEF) » Report

SSEF Gemstone Reports for Coloured Stones

An SSEF Gemstone Report is issued for a single loose gemstone, including diamond when the 4C's are not required. Gemstone Reports are issued only for natural stones (no synthetic or imitation material) and contain:

• Weight
• Shape and Cut
• Measurements
• Colour
• Identification
• Comments concerning the treatment situation
• Colour photo of the stone
  

Special characteristics, either natural (like asterism, colour change etc.) or artificial (like traces of treatments, significant damage etc.) may also appear under "comments".

Since the recognition of the SSEF Laboratory by CIBJO (International Confederation of Jewellery, Silverware, Diamonds, Pearls and Stones) in 1978 we have kept the CIBJO Nomenclature Recommendations as guidelines for our Reports. These rules classify gemstones as natural minerals. Synthetic crystals, in contrast, are not considered gemstones, and their name must be always preceded by the word "synthetic". When we identify "emerald" on our reports, it means that the stone is of natural formation. It is not our standard to use terms like "natural, genuine or precious" when we give the identification.

On request and under favourable conditions, we may put our opinion of the origin under comments. The determination of origin requires additional analytical tests and thus is a supplementary service.

Determination of colour authenticity of diamonds:

In order to determine whether a diamond is of natural or artificial colour, the following investigations are routinely performed on loose stones:

• Thorough observation with a binocular microscope in dark field, transmitted light, polarized light, and immersion (if necessary)
• Quick test with a spectroscope
• FTIR spectroscopy to determine the type of diamond (type IaA, IaA/B, IaB, Ib, IIa, IIb), the presence or absence of C-H stretching bonds and the presence or absence of irradiation/annealing absorption peaks (H1b, H1c) and other infrared characteristics.
• UV-visible-near-infrared spectroscopy of the diamond, cooled down to approximately -130°C.
• Photo-Luminescence spectroscopy of the diamond, cooled down to approximately -130°C.