How GIA Cut Grades Work

GIA Grading
GIA Cut Grades

Shopping for diamonds can easily turn into an exciting experience. It can become hard choosing a single diamond out of a bunch of beautiful gemstones shining brightly at you from all those glass cases at the jeweler. Comparing the technical aspects of each can ease the process considerably, so when it comes to selecting a stone, it is best to have thorough knowledge on the 4Cs of diamond quality.

A GIA grading report would prove helpful when you go about this; there would be a separate one for each graded diamond. Each report would give you a detailed description of the quality of the diamond it accompanies.

The Diamond Cut Quality

It would only be a minor stretch describing a diamond as an arrangement of angled mirrors. The round brilliant cut diamond is made up of about 57 or 58 such mirrors. Gemologists call these angled structures as diamond facets, and it is these facets that reflect the light that falls on and into a diamond. It would break down the white light into a colorful spectrum as well, and reflect that back to the viewer. You would be able to see this light play when you tilt a well cut diamond. It is the facets that ultimately determine cut quality, and you would get sparkle out of a diamond based on the size, angles, and arrangement of these.

Diamond Cut Grade

GIA takes many things into account before deciding diamond cut grade.

  • The way the diamond responds to light is very important. This would determine the brightness (amount of white light reflected), fire (spectrum of colors made by scattering light) and scintillation (light and dark patterns made by reflection) of the diamond.
  • The way the diamond is faceted, crafted, and designed. This would include the weight of the diamond in carats, the thickness of girdle, symmetry in the arrangement of the facets, and the quality of facet polish.

GIA Cut Grading Methods

In the GIA’s official cut grading method, well-trained graders determine the cut quality of the diamond using well-calibrated optical measuring devices and visual observations, in order to access the data relating to the diamond’s cut quality. The optical measuring device would capture images of the diamond, totaling 400 contour images that are then arranged as to get a full 3D image. GIA makes use of this to evaluate symmetry, polish and griddle thickness of the diamond.

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