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What is Diamond Symmetry and How is it Graded

By Mike Fried,

Diamond symmetry refers to how precisely the various facets of a diamond align and intersect. This can include factors such as how the edges align, whether the facets are uniform in shape and size, and how the facets meet at the points and corners. Essentially, it’s a measure of a diamond cutter’s skill in crafting a well-proportioned diamond. High levels of symmetry are crucial for maximizing a diamond’s brilliance, fire, and overall visual appeal.

When shopping for a diamond, look for grading reports that offer symmetry ratings. These are generally ranked on a scale from ‘Poor’ to ‘Excellent’ by major diamond labs like the GIA. If you’re aiming for a diamond that offers the most brilliance and fire, it’s advisable to look for a symmetry grade of ‘Very Good’ or ‘Excellent.’ In terms of price, diamonds with higher symmetry grades are typically more expensive, as they require a higher level of craftsmanship. This cost can be justified by the superior light performance and overall appearance of the stone. Therefore, it’s worth investing in a diamond with good symmetry to ensure you are getting a stone that will truly sparkle.

Diamond Symmetry Chart
To help you with the diamond buying process we lean on our expertise and experience. The author of this article, our CEO, Mike Fried has over 20 years of experience in the diamond industry. Mike started from the bottom, sorting and evaluating hundreds of thousands of diamonds to learn every facet (pun intended) of diamond quality and value. Mike followed that up by spending years buying and selling diamonds on the wholesale market as well as selling tens of millions of dollars worth of diamonds to diamond retailers.

How does Symmetry impact a Diamond?

Symmetry impacts how well a diamond interacts with light and how brilliant a diamond is. A diamond with good symmetry allows light to travel through the diamond as it should. Light bounces off the facets and angles, back through the table to your eyes.

A diamond with poor symmetry sends light through at defective angles, meaning light might exit through the bottom or sides of the diamond. When light doesn’t reflect back to the eye, the diamond looks dull. That’s why symmetry is critical to the beauty of a diamond.

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How Symmetry is graded in Diamonds?

Symmetry grades are measured by the GIA as Excellent, Very Good, Good, Fair and Poor. According to the GIA, a diamond’s symmetry grade is based on the visibility and presence of deviations at 10x magnification (a standard jeweler’s loupe). Several aspects come into play when a diamond is graded for symmetry, including misalignment, missing facets, variation in the thickness of the diamond’s girdle, extra facets and an off-center table.

Here’s a breakdown of the symmetry grades:

Excellent: Diamonds with Excellent symmetry have very few, if any, deviations. Their tables are centered and they don’t have any extra or missing facets.

Very Good: Diamonds with Very Good symmetry have a couple of slight deviations. There might be a slight misalignment or a misshapen facet.

Good: Good symmetry diamonds have a few deviations. The brilliance of the diamond might be impacted by aspects such as a pavilion angle variation or a missing facet.

Fair: Fair symmetry diamonds have several deviations. The brilliance of the diamond is lowered by misalignments, variations and misshapen features.

Poor: Diamonds graded with Poor symmetry have several obvious deviations. The diamond is likely to look dull. It could have a combination of an off-center table, missing facets, variations and misshapen facets.

Is Diamond Symmetry any more important than Polish?

The simple answer to that question is: not really.  Take a look at the diagram above.

Each of the problems mentioned there (off-center culet, off-center table, misshapen facets, out-of-round circumference, crown and pavilion misalignment, and a wavy girdle) can definitely take away from the beauty of a diamond. That’s not the issue.

Telling the Difference between Diamond Symmetries 

The issue is that I, the diamond expert with 6+ years of experience can hardly tell the difference between a diamond with “Good” symmetry and “Excellent” symmetry.

You will only see noticeable defects in symmetry as found in the diagram above in diamonds with a “Fair” or “Poor” symmetry grade.  So like Polish, there’s no need to spend any additional money to buy a diamond with a “Very Good” or “Excellent” symmetry grade.

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About the author

Mike Fried Mike Fried Mike Fried has over 25 years experience in the diamond industry working with Leo Schachter Diamonds, Moshe Namdar Diamonds, and joining The Diamond Pro in 2007. He is recognized as an industry expert and has been quoted in publications such as Us, People, Page Six, The Next Web and more.

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