What is diamond symmetry?

T he arrangement and compliance of the facets in a diamond stone are known as diamond symmetry. Factors like shape, size, alignment of the crown and pavilion, and positioning of the culet that sits with the table also make up the overall symmetry of the diamond

All diamonds are not symmetrical, but the diamond industry specializes in cutting diamonds that are identical to each other for better sales. There are many factors accounted for when cutting a diamond, like keeping its weight intact and avoiding any extra inclusions. The funny thing about symmetry is that to make a diamond look more appealing, the diamond cutter would have to sacrifice its symmetry.

Gemologists observe the diamond under high magnification to examine the stone and rank it according to the diamond’s symmetry. The stones are ranked as “Excellent”, “Very Good”, “Good”, “Fair”, or “Poor”. Many jewelers generally prefer selling “Excellent” and “Very Good” diamond stones, but in reality, they earn most of their revenue on the lower grade diamonds.

Image of a Round-cut Diamond reflecting light
Image of a Round-cut diamond.

How does symmetry affect the diamond?

Gemologists have to use 10x magnification to really see the flaws in the diamond symmetry. Though there are no specific errors or misaligned edges you can spot easily, you can certainly tell when the diamond is not symmetrical. The symmetry of an “Excellent” and sometimes “Very Good” diamond is very significant as the facets and girdles, when cut right, guide the light through the diamond and give it the sparkle. If you ever want to tell if a diamond is symmetrical or not, then observe it under some light and notice the sparkle.

Symmetrical diamonds give out a unique sparkle. An asymmetrical diamond will fail to meet the fundamental criteria of its shape. Round diamonds may look more oval.

Image of a Marquise-cut diamond with diamond accents on the band
Image of a Marquise-cut diamond with diamond accents on the band.

How does diamond symmetry affect the price?

Generally, the cost of a diamond is majorly influenced by the symmetry of the diamond. The cost per carat increases as the quality of the diamond improves. When the diamond is cut professionally, a lot of the rough material is removed from its surface, while the facets are polished thoroughly.

Initially, the weight of the diamond plays a major role in its price. When the diamond is being polished for a better surface, the removal of all the rough material might also remove a large amount of weight of the diamond. So cutting the diamond while retaining its weight heavily adds on to the price of the diamond.

In addition to that, skilled labor, extra resources, man-hours, all sum up the price of the diamond. In the end, economics and profit are the only things that drive this industry. In reality, it is not economically logical for cutters to make every single diamond piece symmetrical. This is because, cutting the diamond while retaining its weight is a rare craft and hence, the markets are flooded with uncut and rough diamonds sold solely for their weight.