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Diamond Symmetry and Polish

by Haley Anhut
Last updated on August 26, 2023

Every diamond is graded based on 4 characteristics, also known as the 4 C’s. Cut, clarity, color, and carat all determine the value of a diamond and are important to become familiar with if you are looking to make this purchase. While all four characteristics are important to consider when looking at a diamond, cut has the greatest effect on a diamond’s beauty and sparkle. Often confused with diamond shape (round, oval, etc.), cut actually refers to how well a diamond is, well, physically cut. This ultimately affects the way diamond facets interact with light. When a diamond is cut, it is then evaluated on its brightness, fire, and scintillation, which are all a result of its symmetry and polish.

Diamond Symmetry and Polish Basics

Polish refers to the smooth, glass-like condition of the diamond’s surface. Diamond polish occurs during the cutting process, and while you may think all diamonds are smooth looking, this is actually due to the work of incredible craftsmanship. A diamond cutter will do their best to achieve a smooth, even polished finish. It is nearly impossible to have a perfectly polished diamond, but a diamond with “excellent” or “very good” polish, will have better fire or brilliance. And while diamonds are extremely hard, they are prone to scratching. This is why it is important to take your diamond off when participating in high impact activities, to avoid any damage. Some people opt for a more protective setting style, like a bezel setting, to further protect their diamond. 

Diamond symmetry refers to how the facets of the diamond are arranged, their size, and their placement on a diamond. A diamond with excellent symmetry means that the diamond is not out of shape, and has facets that are perfectly proportioned and sized. A diamond with poor symmetry will have facets that are proportionally imperfect, which will affect the way light is reflected from the diamond making it appear dull. Having an asymmetrical diamond can make round diamonds appear oval. If you’re in the market for a fancy cut diamond such as a marquise or pear-shaped diamond, it’s vital to pay attention to symmetry. 

Same as diamond cut, symmetry and polish are graded on a scale ranging from “Poor,” to “Excellent.” Both of these characteristics are achieved during the finishing process of a diamond. 

Are Symmetry and Polish Important?

Because symmetry and polish influence cut grade, it is important to become familiar with these terms. Since cut is one of the more important characteristics of a diamond, symmetry, and polish inevitably become important since they affect the appearance of a diamond. 

Information about symmetry and polish can be found in the details section on any diamond page you’re viewing on the Clean Origin site. There are many educational resources as you shop for affordable lab made diamonds.

Which Is More Important?

Because there are so many factors when choosing a diamond, it’s important to know what aspects to give more weight to. Between symmetry and polish, while both important, it’s recommended to choose a higher symmetry rating. While polish has an impact on the beauty and brilliance of a diamond, it doesn’t hold as much weight as symmetry. Symmetry, on the other hand, impacts how well light is reflected off a diamond. When a diamond is asymmetrical, this will affect its overall sparkle. 

However, do not feel that you must purchase a diamond with an ‘excellent’ symmetry grade. The difference between a ‘very good’ and ‘excellent’ symmetry grade can be negligible. This is especially true if you’re looking at fancy shaped diamonds, like rectangular shaped diamonds, as it is difficult to find perfect symmetry. And while there may only be a slight difference between diamonds with ‘excellent’ and ‘good’ grading, this could increase the diamond price up to 15%. However, note that diamonds with a ‘poor’ diamond grade should be avoided, as these diamonds have visible defects and misaligned facets. 


While symmetry and polish are important characteristics of a diamond, try to avoid getting caught up in the nitty-gritty of it all. With so many factors to keep in mind during your diamond search, it can all get very overwhelming. Remember, no diamond is flawless, so pick the diamond that you feel looks the most beautiful. As always if you need guidance, our team is here to help.