GIA: Newsroom: Insider April 28, 2006; From the GIA Laboratory

Figure 4. These girdle profile examples illustrate the extent of painting allowed for each of the top four cut grade categories. A diamond with a girdle profile more irregular than “severe” would not lower the cut grade beyond “fair.” To download a larger pdf of figure 4 and 5, click here.

Figure 5. These girdle profile examples illustrate the extent of digging out allowed for each of the top four cut grade categories. A diamond with a girdle profile more irregular than “severe” would not lower the cut grade beyond “fair.” To download a larger pdf of figure 4 and 5, click here.

Figure 6. Symmetry faults make it difficult to assess the extent of painting and/or digging out in a round brilliant such as the one on the left, although the faults themselves are readily apparent when the diamond is compared to a standard round brilliant (right). Diamonds with symmetry faults such as these are visually assessed on an individual basis to determine the relationship between their symmetry rating and the extent of their painting and/or digging out.

Figure 7. Naturals or extra facets at the girdle can also interfere with the assessment of the extent of painting and/or digging out. Diamonds with naturals or extra facets such as those shown are visually assessed on an individual basis to determine the relationship between these features and the extent of their painting and/or digging out.

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