The Diamant Prüflabor GmbH Idar-Oberstein grades polished diamonds according to the rules of the International Diamond Council (IDC). The IDC was founded in 1975 by the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufactures Association (IDMA), in order to develop detailed grading rules from practice. These so called IDC-rules were accepted from the WFDB and IDMA in 1978 and updated in 2008. The IDC rules are recognized by all diamond bourses world-wide.

The DPL was founded in 1977 with the intention to establish the IDC rules in Germany. From the beginning the diamond trade and the customers could trust the quality of the DPL-certificates, which also had become evident through the unlimited liability of the correctness of the certificates.

The official confirmation for the quality of its work was obtained by the Diamant Prüflabor Idar-Oberstein through the accreditation as a recognized testing laboratory.

The DPL has been officially accredited in February 2002 by the DAP (German Institute for Accreditation Test Procedures) as providing legitimately its results according to the international standard DIN EN ISO/IEC 17025:2005 for grading of polished, unmounted natural diamonds.

Thus, the DPL is the first laboratory and still the only one in Germany for which the competence for quality examination of polished diamonds has been officially confirmed by means of accreditation according to an ISO standard.

Requirement for such an accreditation is the development of a management system for the test methods procedures in administration and in the lab as well. The quality manager developed all the respective rules and regulations and compiled these in the management manual. These are in particular qualifications and special training measures for the staff, and also preventive actions to avoid mistakes.

The detailed policies and procedures demand calibrated test methods and reference stones. Tools and equipment must always represent the state-of-the-art technology and must be checked at regular maintenance intervals.

Regular international audits take care that any occurring faults or shortcomings of the QM-System will be uncovered and corrected by preventive actions.

Annual intermediate inspections grant that the standards are met.

The anonymous assessment of the diamonds in the laboratory through several graders ensures strict neutrality and objectivity without regards for the person.

The diagnosis of the various methods of treatment like changes of the degrees of purity or colour, are also a prerequisites for an efficient testing laboratory, as well as the distinct identification of imitations or synthetic diamonds.

Of course the DPL does not assess the value nor it is engaged in the trade of diamonds.

As an additional service, the DPL offers services for re-polishing diamonds with renowned diamond manufacturers.