SSEF introduces new policy for ruby certificates

In the light of new developments we have re-considered our terminology used for ruby treatments in SSEF test reports. The recent way of disclosing heat treatment and presence of artificial glassy residues and fillings, as applied during the last three years, has been published in SSEF Standards & Applications (1998). The terms "extent of enhancement" was taken over from the emerald area where the enhancement is fully covered by the filling of fissures.

The ruby treatment is, however, a more complex process, where heat together with flux-like substances act in different ways to enhance the treated stones. Heat alone may change the colour and transparency of the ruby. The application of flux like materials leads in most cases to an artificial healing of fissures, and leaves glassy residues in fissures or fillings in larger cavities. What we can see with magnification is usually the presence and amount of these glassy residues. The amount of residues is not related to the heat applied but rather to the amount of cracks originally present in the ruby.

The total enhancement is thus a combination of transformation of colour, increase of transparency and healing of fissures or fillings in of larger cavities. To establish a "ruby enhancement scale" based on judging the presence of foreign residues alone is thus incorrect. It would only give a degree of the amount of trapped flux, and not reflect the changements achived by heat (colour) or transparency (e.g. dissolved silk). We therefore change mode of putting "extent of enhancement: minor, moderate, significant" to "amount of residues: minor, moderate, significant". The formula "with indications of thermal enhancement" stays unchanged for heated stones with recognisable thermal treatment.

We think that a general statement on the "extent of enhancement" which should englobe improvements of colour, transparency and healing fissures, is not feasible. An indication of a heat treatment and a gradual disclosing of glassy residues found is at this point the best practical formula to express what a dealer needs to qualify a heated ruby.