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Diamond Industry Organizations: The International Diamond Council

Diamond Industry Organizations: The International Diamond Council

The International Diamond Council (IDC) is a diamond industry organization formed to establish industry-wide unity in the grading of polished diamonds. Its beginning was as a joint committee, formed at the 18th World Diamond Congress of the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufacturers Association (IDMA), which was held in Amsterdam in 1975. This committee was later named the International Diamond Council.

The decision to form the IDC came after confusion started to develop in the market when the number of private laboratories grading diamonds grew at a high rate, and each seemed to be claiming that its standards were the best and its results the most reliable. A growing number of diamond industry stakeholders were alarmed by this practice, and many started to voice a desire for standardization of the terminology and definitions used to characterize diamonds.

The IDC’s mission is to formulate a set of internationally recognized standards for diamond grading and nomenclature that would be applicable uniformly worldwide. In addition, it works to normalize working methods for the application of those standards, as well as encourages recognized grading laboratories to apply those standards and methods.

Experienced diamond cutters and dealers from Amsterdam, Antwerp, Idar-Oberstein, Johannesburg and Ramat Gan were asked to work out reliable and clear "guidelines for grading polished diamonds." Three years after its formation, during the 19th World Diamond Congress in Tel Aviv in 1978, a set of basic principles called the International Rules for Grading Polished Diamonds was proposed for ratification by the WFDB and IDMA general assemblies. The rules were unanimously approved.

The IDC Rules start with a set of definitions. First, it defines what a diamond is. It then defines a treated diamond, stating that it is “a diamond that has been subjected to a treatment process, other than cutting, polishing and cleaning, intended to possibly change the diamond’s appearance or other properties.” Such treatments include filling, drilling, and coating a diamond. Putting a diamond through a high pressure, high temperature (HPHT) process, which can alter a diamond’s color, is also a treatment.

The IDC Rules go on to require disclosure of such treatments or if a diamond is lab-grown, and defines the language that laboratories should use to disclose this.

Other definitions include the language for stating clarity and a definition for each grade, the terms to be used for depth of color in colored diamonds, fluorescence, and even what the measurements used to define the grade of a diamond’s proportions are. The rules go on to define many more characteristics of diamonds that are assessed by diamond grading laboratories. Even how diamond weight is expressed and when the weight is rounded up or down is defined by these rules.

The International Rules for Grading Polished Diamonds were fully adopted by three labs, which then began to comply with them: the Diamond Lab of HRD in Antwerp, the Jewellery Council of South Africa in Johannesburg, and the Diamant Prüflabor (DPL) in Idar-Oberstein. These three labs, and especially HRD, carried out the research to develop and update the IDC rules.

Over the years, the IDC continued to monitor changes in the diamond industry, and 30 years after the original rules were approved, an updated version of the International Rules for Grading Polished Diamonds, was proposed by IDC. This updated version was approved by the WFDB and IDMA in 2008. In 2010, the rules were further amended to incorporate changes that resulted from industry-wide consultations on diamond nomenclature.

The updated version of the rules allows for the diamond grading laboratories to choose between three terms: "laboratory-created," "laboratory-grown" and "synthetic" to describe a diamond that was not mined and created by nature. By amending its reference document, the IDC has incorporated the CEN Workshop Agreement on consumer confidence and diamond nomenclature.

The updated IDC Rules can be found on the IDC website here.

Despite these achievements, the IDC is not resting on its laurels. New discoveries, changing needs and further clarifications are always required. Therefore, an updated version of the IDC rules is being considered and will be tabled at an upcoming World Diamond Congress.

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