What Is Diamond Symmetry?

What Is Diamond Symmetry?

Have you heard the term ‘ Diamond Symmetry ‘? Anyone who has shopped for a diamond before has at least heard of the “Four Cs” … but jewellers often don’t mention some of the other factors that contribute to the price of a diamond. That’s not to say those jewellers have hidden agendas or are trying to hide anything – It’s often simply a matter of not wanting to overwhelm shoppers, especially first-timers, with too much information. After all, it can be difficult enough just to remember and prioritize among diamond color, cut, clarity, and carat weight.

Another oft forgotten but no less important factor is diamond symmetry. Symmetry affects the aesthetics of diamonds and, therefore, also affects their cost or value. Symmetry refers to the way the various facets or surfaces of a diamond align and intersect. It may include extra facets, off-center culets, wavy girdles, and off-center tables.

The symmetry of a diamond directly impacts its brilliance. Inferior diamond cuts lead to poor symmetry. As a result, when light enters the diamond, it is sent off in slightly odd or improper angles as it refracts around the interior of the diamond.

Diamond symmetry Grading

The GIA grades the symmetry of diamonds from excellent to poor, as seen in the diagram below:


Excellent No symmetry defects visible at 10x magnification
Very Good Any defects are extremely difficult to see at 10x magnification
Good Any defects are difficult to see at 10x magnification
Fair Defects are noticeable at 10x magnification and may be visible to the naked eye (these are not offered by Loyes Diamonds)
Poor Defects are visible to the naked eye (these are not offered by Loyes Diamonds)


Some argue that symmetry will have little effect on the performance of the Gem, but at Loyes we feel that everything should be perfect or near perfect, in order for the diamond to perform to the best of its ability. If a Jewel is lacking in one area, such as symmetry, then it will have a corresponding negative effect on other areas, such as the cut. These shortcomings are particularly noticeable in diamonds with a higher clarity grade, such a vvs1 or vvs2.

The symmetry of a stone will have a notable effect of the price of the stone. An “excellent” symmetry grade demanding 10% to 15% over a gem with “good” symmetry. Many argue that the premium of 15% is based more on the clients’ perceptions that they are getting a far superior stone than on the actual increase of the effect on the diamond.

At Loyes, we speak openly with clients about a diamonds symmetry but feel strongly that the ‘cut’ of the Gem should take president. This is because the cut grade of a diamond also encompasses both symmetry and polish. If a stone has an excellent or very good cut it will also have an excellent or very good symmetry.


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