The Ideal Cut diamond is based on “triple ideal” parameters where the diamond is
“excellent” in all three ratings:
- Proportion - girdle thickness, culet size, table %, total depth %, crown angle, pavilion angle;
- Finish - polish and symmetry;
- Direct Light Assessment - optical brilliance
and optical symmetry.
The GCAL Ideal Cut standard includes the traditional values of proportion and finish
and adds a third dimension based on direct assessment optical light performance,
which is perhaps one of the most useful descriptive and selling tools in today’s
With this new certificate, GCAL is seeking to resolve the issue of the
many revisions over the years to percentages and angles that have constituted the
‘theoretical’ ideal cut diamond, which changes perhaps confused the many gemologists
and diamond dealers using the ‘ideal’ term, and add perhaps one of the most important
analysis tools that can actually assist in selling the diamond. The GCAL Ideal Cut
diamond certificate sets a standard for ideal cut diamonds that will generate higher
confidence among buyers and sellers – as well as higher value, greater demand, and
ultimately, greater sales and profits for jewelers.
GCAL’s optical light performance system measures and analyzes actual light return
and optical symmetry that reveals the cutter’s craft, and allows buyers and sellers
to judge the mosaic of facets that reveal a true ideal cut diamond’s maximum beauty.
According to recent educational literature, “it is important to place more emphasis
on the way the diamond actually looks than on its numerical parameters.”