This document shows in details how DiamCalc grades diamonds

When a diamond data is entered, DiamCalc uses a selected grading system ("appraiser") to grade each diamond parameter according to tables below. Depending on parameter value, it is given a grade (different grading systems have different quality groups). Then the quality of the diamond cut is calculated as the worst of quality groups of all individual parameters.

This data is contained in Appraise.txt file in the folder where DiamCalc is installed.

There are two kinds of data tables: appraiser tables and translation tables.

Appraiser tables shows how each individual parameter is graded. They contain following columns: parameter name, as it is listed in Appraise.txt file; the meaning of the parameter; and one column that lists a range of that parameter for each quality group.

Translation tables give a numerical equivalent for quality groups of some parameters, for instance, they could define a "thick" girdle as having size between 4.75 and 6.25 percents of the diameter.

Tables are ordered by grading system, then by cut. The following systems and cuts are implemented:

HRD system : Brilliant cut; GIA system : Brilliant cut,

AGA system supported cuts are :

Brilliant (different tables for diamonds less than 0.5 ct or 0.5 ct. and more),
Pear, Heart, Oval, Marquise, Prince, Emerald and Radiant).