A detailed understanding of diamond symmetry

Posted by Hari Krishna

November 30, 2022

Telling one diamond apart from the other is not easy, especially because they look identical and at the most, it is usually a grading report that can reveal the differences. Symmetry is something that is taken into consideration while determining the quality and value of a diamond and reflects in a grading report.


Diamond Symmetry is one of the important elements to look at in a diamond. But how can we know the symmetry in a diamond? Can one see it? Unlike cut, color, or clarity, it’s difficult to tell the difference between a diamond with a “good” symmetry rating and one with an “excellent” symmetry rating. 


Before we get into the details, we need to understand what exactly this concept means. 


What is diamond symmetry? 


Symmetry in a diamond is a combination of different aspects of its structure. It is how the diamond comes together and forms a shape which actually depends on precision of the cutting and overall craftsmanship. 


Let’s understand the individual aspects to fully understand diamond symmetry. 


  • Facets: A diamond facet is the flat surface of a diamond’s shape. Every diamond has multiple facets that allow it to absorb and reflect light in different ways. 


  • Culet: The culet is the tiniest facet of a diamond and is found at the bottom of the diamond.


  • • Table: The table of a diamond is the stone’s largest facet, consisting of the flat surface on top. To obtain the table percentage, divide the diamond’s top facet width by the stone’s total width.


  • Crown: The crown is the angled edge of a diamond that lies between the girdle plane and the table.


  • Pavilion: The pavilion of a diamond is the lower part of the diamond’s ‘V’ shape.


  • Girdle: The thin perimeter of a diamond that separates the crown from the pavilion is known as the girdle.



The precision with which a diamond’s facets align and intersect is referred to as symmetry. It is defined by how symmetrical the facets and angles of a diamond are. Is the table’s culet centered? Is the size and shape of all the facets uniform? Based on these things, the grade of symmetry is determined by a gemologist. 

Extra or misshapen facets, off-center culets and tables, and wavy girdles can all be examples of asymmetrical diamonds which can also be known as symmetry defects.


Diamond Symmetry Defects

  • • Off-Center Culet: The diamond’s bottom point is not exactly in the middle. The diamond pavilion might get reduced light due to this defect. 



  • Off-Center Table: The top of the diamond’s table facet is not perfectly centered. The overall diamond’s light performance may be impacted.



  • Misshapen Facets: The pattern is not symmetrical, and the skit and triangular-shaped facets are uneven. The amount of light that passes through each diamond facet is affected by this.



  • Out-of-round girdle outline: This defect is seen when a round-cut diamond is improperly shaped, with a length-to-width ratio greater than 1.10.



  • Crown and Pavilion misalignment: The crown and pavilion facets should be aligned at the girdle points, but they are uneven. This has the potential to alter the way light bounces in the diamond. 



  • Wavy Girdle: The girdle of the diamond is not in a straight line around it. The symmetry of a diamond’s setting might be affected by this.


    How is symmetry graded?


    The GIA assigns symmetry grades of Excellent, Very Good, Good, Fair, and Poor. The visibility and presence of deviations at 10x magnification are used to determine the symmetry grade. 


    Let’s learn about some of the factors of the diamonds’ symmetry grading, defined by GIA.


    Excellent: Excellent symmetry means that there are very few deviations in a diamond. Their tables are perfectly centered, with no extra or missing facets.



    Very Good:Very Good symmetry diamonds have a couple of minor flaws. A slight misalignment or a misshapen facet could be present.



    Good: Diamonds with good symmetry have a few deviations. A pavilion angle variation or a missing facet could have an impact on the diamond’s brilliance.



    Fair: Diamonds with fair symmetry have several deviations. Misalignments, variations, and misshapen features reduce the diamond’s brilliance.


    Poor: Diamonds with a Poor symmetry grade have several noticeable flaws. The diamond will most likely appear dull. An off-center table, missing facets, variations, and misshapen facets could all be present.


    Effects of Symmetry on diamonds 


    Symmetry of a diamond is determined by its cut quality. The criteria outlined in the AGS and GIA grading systems are a fantastic resource when looking for a stone that meets your needs.


    The value of a diamond is affected by every aspect or characteristic that is used in the grading process. Diamonds with “Fair” or “Poor” symmetry are generally considered to be less valuable.


    Symmetry depends on the expertise of the craftsmen who plan, cut and polish a diamond. So if you are looking for the best and most symmetrical diamonds, choose the right diamond manufacturer. 


    Looking for high-quality symmetrical natural diamonds? 


    Hari Krishna Exports is among the top 10 diamond companies of India and largest exporters of GIA certified loose diamonds, ranging from 0.18 cent to 50+ carats-sized diamonds in more than 9 shapes, including brilliant-round cut, FL to I3 clarity, and D to M Color across the 80+ countries of the world, including the USA, Hong Kong, China, Australia, Israel, the UK, Canada, etc.


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