Also referred to as a diamond grading report, diamond dossier or diamond quality document, the certificate contains a detailed analysis of the diamond's size, cut, colour, clarity, florescence, finish and other relevant characteristics.
The most widely acknowledged certification laboratories include:
The GIA (Gemological Institute of America)
The GIA is an independent, non-profit organisation, whose grading system has become the benchmark for the international gem and jewellery industry. Created in the 1950's, the GIA grading system uses uniform criteria to provide unbiased opinions on the quality of polished diamonds.
HRD (Diamond High Council - Hoge Raad voor Diamant)
Antwerp is world famous as a leading diamond centre. The HRD, or Diamond High Council, is a non-profit organisation representing the Belgian diamond industry and trade. Its certificates are valued worldwide as a guarantee of authenticity, conforming to international standards.
IGI (International Gemmological Institute)
Established in 1975 in Antwerp with a network of labs in a number of different countries. It has developed into the largest independent gem certification institute, with a worldwide reputation for reliability and integrity.
GEM A (Gem Testing Laboratory of Great Britain)
Reports from this lab are based on the principles of "harmonized grading" for colour and clarity of diamonds and provide all the essential information you will need. This is also the only laboratory in the UK registered by CIBJO to issue CIBJO Diamond Grading Reports.
BGI (British Gemmmological Institute):
An independent laboratory accredited by the UK Government's Deptartment of Trade & Industry (DTI). The BGI offers a wide selection of reports suitable for a variety of needs ranging from loose diamonds and coloured gemstones through to mounted jewellery appraisal and valuations.