GIA, HRD and IGI are prestigious international organisations that certify a diamond’s quality, based on the four C’s rating system. In addition to a GIA, HRD or IGI certificate, we also provide an ISTANBOULLI GIOIELLI Certificate. This certificate indicates precise data on the cut, the clarity, the colour and the carat weight of the diamond and any other precious stones used in our creations. These certificates guarantee the authenticity and integrity of an ISTANBOULLI GIOIELLI diamond.