The whiter a diamond, the more exceptional it is considered. A diamond’s colour ranges from D to Z in alphabetical order, with D being exceptionally white or colourless and Z being a tinted colour or yellow. ISTANBOULLI GIOIELLI classifies its diamonds by using a GIA (Gemological Institute of America), HRD (Antwerp Institute of Gemology) and IGI (International Gemological Institute) colour grading chart. Only diamonds with “J” colour or above are accepted by ISTANBOULLI GIOIELLI, meaning that all the diamonds selected for our creations are colourless or near colourless.