n the new Gemological Institute of America (GIA)
Diamond Cut Grading System for standard round brilliant
diamonds, the aspect of craftsmanship — i.e., the
care that went into the crafting of a polished diamond,
as seen in its finish — plays an important role in the overall
cut grade along with the other aspects of face-up appearance
and design (see figure 1).The two categories that define
finish — polish and symmetry — have been part of GIA’s
International Diamond Grading System™ since its inception
in the mid-1950s and are listed on each GIA Diamond
Grading Report and Diamond Dossier®. It is important
to note that with the introduction of the new cut grading
system, the criteria for determining polish and symmetry
remain the same.The following is a review of the criteria
and the methods used for assessing them, and will explain
their role in the new cut grading system.This article expands
on the GIA’s course material for assessing polish and symmetry,
describes the guidelines used by the GIA Laboratory
in evaluating finish and presents specific examples of
the different polish and symmetry categories.
In the GIA Diamond Grading System,“polish”refers to
the quality of a diamond’s surface condition as a result of
the polishing process (see figure 2) or to blemishes created
after the cutting process, often referred to as “wear and
tear” (see figure 3).Polish features are located on the surface
and do not visibly penetrate into the diamond at 10X
magnification. Polish is assessed on a scale consisting of
excellent, very good, good, fair and poor.“Symmetry”
refers to the exactness of the shape of a diamond, and the
n the new Gemological Institute of America (GIA)Diamond Cut Grading System for standard round brilliantdiamonds, the aspect of craftsmanship — i.e., thecare that went into the crafting of a polished diamond,as seen in its finish — plays an important role in the overallcut grade along with the other aspects of face-up appearanceand design (see figure 1).The two categories that definefinish — polish and symmetry — have been part of GIA’sInternational Diamond Grading System™ since its inceptionin the mid-1950s and are listed on each GIA DiamondGrading Report and Diamond Dossier®. It is importantto note that with the introduction of the new cut gradingsystem, the criteria for determining polish and symmetryremain the same.The following is a review of the criteriaand the methods used for assessing them, and will explaintheir role in the new cut grading system.This article expandson the GIA’s course material for assessing polish and symmetry,describes the guidelines used by the GIA Laboratoryin evaluating finish and presents specific examples ofthe different polish and symmetry categories.In the GIA Diamond Grading System,“polish”refers tothe quality of a diamond’s surface condition as a result ofthe polishing process (see figure 2) or to blemishes createdafter the cutting process, often referred to as “wear andtear” (see figure 3).Polish features are located on the surfaceand do not visibly penetrate into the diamond at 10Xmagnification. Polish is assessed on a scale consisting ofexcellent, very good, good, fair and poor.“Symmetry”refers to the exactness of the shape of a diamond, and the
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