The symmetry of a diamond has a direct impact on the pattern of reflection and this pattern of reflection affects the scintillation (how light is reflected off a facet) of a diamond. In fact, there is a romantic-sounding but actually quite practical term for diamonds showing a perfect pattern; these diamonds are known in the trade as ‘hearts and arrow’ diamonds. They are called this way because of the appearance of 8 hearts when looking down on the pavilion, and a set of arrows when looking at it from under the table. If your diamond is called ‘H&A’, it means your diamond has excellent optical symmetry.
Arrows are seen when a symmetrical diamond is viewed from the top
The modern round brilliant cut is a very symmetrical cut, which means that no matter how you divide the diamond, the arrangement of facets will follow a symmetry, or in other words, both halves will resemble each other when the diamond is visually divided. If the diamond has any feature that affects this symmetry, the symmetry grade is also affected. The common features that might affect the symmetry of a diamond are listed here: Table Off-center, Culet Off-center, Table/Culet Alignment, Irregular Girdle, Out of Round, Extra Facet, Irregular Facet, Open Facet, and Misalignment.
Out of all of these features, misalignment between the crown and pavilion and open facets are the most common symmetry variations found in a diamond. If your diamond has a ‘no or difficult to see’ misalignment or open facet, your diamond has an excellent symmetry rating.
What can a rating of ‘excellent’ symmetry mean?
As with other attributes, an excellent symmetry rating indicates the dedication and care put into planning your diamond for the cut, and ensures the best possible pattern of reflection in your diamond to make it the most beautiful.
How does symmetry affect the price of a diamond?
Like all other attributes of your diamond, a diamond with an excellent symmetry rating gives you the assurance of a beautifully cut diamond, though a little more expensive than those with a lower symmetry rating.
