Qualities that compromise a diamond's symmetry include off-center culets and tables, misshapen facets, and a wavy girdle. If the crown and pavilion are misaligned, this will also have its effect on the diamond's brilliance.

Symmetry is most important in round brilliant diamonds, and somewhat less so in fancy shapes such as the asscher and emerald cuts. Round diamonds are cut with 57 facets (58 with a culet), and so there is more room for error if they don't align correctly and light is misdirected. Step-cut diamonds are shaped with fewer facets; an Excellent symmetry grade is therefore less of a necessity.

A quality symmetry grade should be considered in diamonds with particularly high clarity grades. While symmetry defects can be very subtle, they may undermine a diamond's otherwise pristine qualities. With lower clarity grades, symmetry should be less of a concern - but still kept in mind.

The GIA grades diamond symmetry on a scale from Excellent to Poor. Excellent, Very Good and Good symmetry grades indicate that defects will be difficult to see, even under 10x magnification. Even a Fair symmetry grade is hard to discern with the unaided eye. Fonder Diamond does not offer diamonds with Fair or Poor symmetry grades, so that you can be sure of your diamond's superior brilliance.

The AGSL has different names for its symmetry grades. Most industry professionals group AGSL Ideal and GIA Excellent into the same category. It is extremely difficult to identify any defects under 10x magnification, unlike the next grade lower where it is very difficult' to identify. The Fonder Diamond inventory sorts diamonds into groups by the GIA and AGS equivalent symmetry grades. This makes it convenient for you to find the right diamond, at the level of symmetry you are comfortable with.