Girdle thickness is somewhat of a judgment call. If a girdle is Medium to Thick, then this could mean 1/3 of it is Medium, 1/3 is Slightly Thick, and the remaining 1/3 is Thick. The term “Medium to Thick” may have several meanings. It may be that 85% of the diamond’s girdle is medium, whereas the remaining 15% is thick. In such a case, the entire adjustment percentage cannot be added into the formula. A stone with a more consistently thick girdle will require you to add a larger adjustment percentage to the formula.
