A 2020 Review of the ICSL Coloured Stones Grading System
Developed by Ian Campbell FGA —- Revised by Jeremy Rothon FGA
Introduction
ICSL is the acronym for ‘Independent Coloured Stones Laboratory’.
The gem trade in South Africa has been the recipient of many ICSL coloured stones grading certificates/reports over a very long period of time. In recent years this demand has increased considerably. It is therefore appropriate that a review be given of this system so that a wider spectrum of users are better informed about it.
Short History
Usage of ICSL Grading System Reports
A Quick Way to Interpret he Significance of the Final Quality Grade
Regarding Copyright
In spite of the copyright nature of this grading system, the Independent Coloured Stones Laboratory and The Gem Lab confirms that there is no legal problem to be encountered by those seriously using and thus recognizing the ICSL system, subject to only two conditions:
- The grading is done correctly within the FULL terms reference of the ICSL system.
- The relevant documents acknowledge use of the ICSL system. (Simple endorsement: ‘Based on ICSL grading parameters’).
Comments: The usage of the ICSL system is encouraged, because it has an established history, is well conceived and sets a good standard for the quality assessment of cut gems. If you would like more information on the ICSL system contact me on info@gemlab.co.za
Questionable Grading Systems
Notwithstanding what is written above, numerous so-called grading systems that have made an appearance in South Africa in comparatively recent times use nomenclature which indicates over-enhanced qualities at almost all significant pro-rata levels on the recognized quality scale. Looking at the prevalence of such, one could even wonder if there are any poorer quality stones left in the market place! Tanzanite in particular is subject to this type of over representation. This type of over-grading is a worrying trend and should not be encouraged. The term so-called used in the above paragraph is because proper terms of reference cannot be found for such ‘systems’. Purely descriptive names relating to grades are all very well, but supporting parameters should be properly defined if they are to relate to a meaningful system. Definitions are very important in this context, in that they afford reasonable stability on an on-going basis.
Worst of all are what could be termed quasi-systems. These show parameters that really do not make much sense, other than to glorify a stone to an absurd degree of high quality. As an actual example, one such parameter relates to clarity grading (of tanzanite in this case), which goes beyond the state of ‘Flawless’ to become described as ‘Flawless +’. How flawless can a stone get?
There are also other similar type overdone grades that parallel this – not only in that particular grading process, but others as well, where highly suggestive alphabetical letters are very misleading to the un-initiated buyer in the way they are presented in the reports.
This leads to an opinion that this sort of thing constitutes an enhanced ‘selling’ certificate or report, whereby a prospective customer is lulled into a false sense of having bought a stone of unusually good quality, when in fact it is well below that status. Such misrepresentation, in the opinion of this writer, does a disservice to both the customer as well as the image of the gem trade, no matter where that happens to be. It is this type of anomalous service that stretches credibility to the limit in the case of meaningful documentation in this context.
THE GEM LAB uses the ICSL (Independent Coloured Stone Laboratory) grading system.
All coloured stones are graded according to the ICSL system as it applies to all gemstones.
The ICSL system was designed to give unbiased professional opinions by qualified gemmologists of the quality of cut gemstones after strictly taking into account the carefully constructed parameters essentially used in the process. It also gives realistic reports in plain English without stating misleading nomenclature that is so often seen these days.
Some large laboratories use the ICSL grading system but generlise the terminology which can cover 3 or 4 grades.
Final Grade
The ICSL system was the FIRST laboratory internationally to give FINAL GRADES, which were in turn based on the of all the other component parameters. The nomenclature ‘Final Grade’ was introduced by ICSL in 1982. Only after the ICSL Coloured Stones Grading System was first published in 1985 in the USA, did the first laboratory, in New York, follow suit. However, this was under the guise of different nomenclature.
A Quick Way To Interpret The Significance Of The Final Quality Grade
One has to look only at the difference, if it exists, between the Colour Grade and the Final (quality) Grade. If there is a downward shift numerically between them, for example ICSL 80 (Very Good) to ICSL 70 (Good), this will immediately have the effect of informing the reader that the stone has been down-graded because of a number of faults that exist. If no faults exist to within the (practical) defined limits, the final grade will not change from the colour grade. In the example given above this would remain as ICSL 80 (Very Good). A stone’s colour grade (and this can vary with the species) dictates its maximum possible final grade. The only exceptions are phenomenon-type stones (such as star ruby or sapphire, to name only two). It is important to use suitable colour comparison stones or other compatible means for assessing the colour grade, provided such are used correctly and consistently.
