The GIA Colored Diamond Grading Report provides a full quality assessment of a coloured diamond including the coloured diamond colour grade, colour origin (natural or treated, such as HPHT processed or artificially irradiated), carat weight, clarity, and a plotted diagram of its clarity characteristics. As an optional service, a full colour image of the diamond may also be included.Unlike GIA’s D-to-Z color grading system, which is based on the relative absence of colour, coloured diamond colour grading is based on the presence of colour. Using a controlled viewing and lighting environment and a comprehensive set of colour comparators, trained graders consistently determine the characteristic colour of a diamond and assign a colour grade (“pink,” for example). The hue chosen is modified by a “Fancy-grade” term, such as Fancy Light, Fancy, Fancy Intense, Fancy Deep, Fancy Vivid or Fancy Dark, which describes the combined effect of tone and saturation.The laboratory issues this report on loose, natural coloured diamonds weighing 0.15 carats or more. The GIA Colored Diamond Grading Report is not issued for laboratory-grown, simulants, mounted diamonds or those that have undergone unstable treatments, such as fracture-filling or coating. Any evidence of other treatment is prominently disclosed in the report.