In 1975, the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufacturers Association (lDMA) created a joint committee to create an international standard for diamond grading rules, working methods and nomenclature. The joint committee later changed its name to the International Diamond Council (IDC).
IDC was founded on the following basic principles:

• A set of internationally recognized standards should be developed, and they should be applicable in the same way all over the world.
• Working methods for applying these standards should be normalized too. This is necessary in order to arrive at uniform certificates.
• Internationally recognized institutes would apply the accepted standards and methods.

As a result of several meetings and discussions in 1975, 1976 and 1977, a first document on the standards as well as on the working methods was drafted in July 1977, and called the "Proposal for Normalizing the Description of Diamonds". In March of that same year, an international series of colour masterstones and corresponding denominations were accepted in agreement with CIBJO, The World Jewellery Confederation.

In 1978, at the 19th World Diamond Congress in Amsterdam, the IDC presented the general assemblies of the WFDB and IDMA: the International Rules for Grading Polished Diamonds. The system was unanimously accepted, and since then has been implemented by major diamond labs.

The International Diamond Council is headquartered in Antwerp, Belgium, and its current chairman is Mr. Harry Levy.

Official International Diamond Council website