Blog Time

Blog Time

Diamond Polish & Symmetry: The Ultimate Guide

When we talk of diamonds, the first thing that comes to mind is their brilliance and sparkle. A “finished” diamond is one that has undergone proper cutting and polish. This is where the expertise and precision of the craftsmen come into play. Thus, diamond polish and symmetry are two factors that contribute significantly to the overall appeal of diamonds.

The Gemological Institute of America lays a great deal of importance on the 4Cs – cut, clarity, color, and carat weight of diamonds. However, apart from these, each GIA diamond report also features a detailed assessment of the polish and symmetry of a diamond. Each diamond is then rated on a scale ranging from Excellent to Poor on the basis of diamond polish and symmetry respectively.

How important is diamond polish?

We all understand that diamonds need to be polished in order to get the final luxurious look. No one spends money on rough, uncut diamonds. A polished diamond brings out the cuts and facets of the stone. This allows light to enter the stone and we experience the “dazzle” which is actually the phenomenon of total internal reflection. While polishing any diamond, tiny bumps and inclusions that might be present on the surface of the stone are smoothened out.

In case a diamond is not unpolished or not polished enough, its facets cannot act as mirrors. So, light is not reflected properly, and the diamond appears dull and ordinary. Due to the distorted light reflections, any blemishes on the surface of the diamond become even more pronounced and make the stone look rough.

How are diamonds polished?

A polishing wheel, which has a function similar to that of a sander, is used to polish diamonds. This polishing wheel actually has a finely ground surface that rubs against the stone that needs to be polished. Most industrial diamonds are polished mechanically in this manner.

You might have also heard of hand-polished diamonds. This is done in cases where diamond grading has revealed that the stone is of excellent quality based on the 4Cs. Here, the diamond is not polished by a polishing wheel, rather it is meticulously polished by hand. This raises the value of the diamond and it will be priced higher.

Diamond polish grades:

Polished diamonds are graded on a scale ranging from Excellent to Poor. Thus, your diamond may fall into any of the following categories:     


There are no visible surface flaws or bumps even under 10x magnification.

Very Good:

The polishing flaws are so minimum that they are only very slightly visible under extreme magnification.


The polished diamond may have flaws that are difficult to spot under high magnification.


The diamond has polishing flaws that are visible to the naked eye when viewed closely.


The polish flaws are quite evident, making the diamond look rough and unfinished.


What is diamond symmetry and how important is it?

Diamond symmetry encompasses a lot of things – the diamond shape, alignment, and diamond cut. While the 4Cs of diamond grading laid out by GIA covers diamond cut, it is worth noting that diamond symmetry plays an equally important role. Very often, while checking for a symmetric diamond, we look for a number of aspects. These could be:

·       Alignment of the crown and pavilion of the diamond.

·       Whether the table and girdle are parallel to each other or not.

·       A straight, uniformly thick girdle

·       Equal angles of the crown between the table and girdle.

There may be many out there to convince you that diamond polish and symmetry do not mean much, and that you can get a better deal on unpolished and symmetric diamonds. But keep in mind that these are two factors that impact diamonds greatly. Diamond polish and symmetry are clearly visible to the naked eye, and any shortcomings on these factors can change the look of the diamond by a vast extent.

How is diamond symmetry graded?

Similar to diamond polish, diamond symmetry too is graded on a scale ranging from Excellent to Poor.

What happens if diamond polish and symmetry are compromised?

·       There is not much difference between a diamond rated “Excellent” and a diamond rated “Good” for its polishing. So, if the diamond looks sufficiently polished and bright to the naked eye, it is better to opt for a lower rated diamond.

·       Diamonds with extremely poor symmetry will have a clear negative appearance. This is because light will not be reflected in the intended manner, making the stone look deformed.  

·       Diamond symmetry therefore, becomes more important than diamond polish. The clarity of the facets and cuts of a diamond are dependent almost entirely to its symmetry.

·       Diamond polish and symmetry in case of colored diamonds are more flexible. Very often, if the diamond is heavily tinted, it can make allowances for lower grades of diamond polish and symmetry.

·       Off-center tables or uneven thickness of the girdle can easily reduce the value of any diamond.

·        As mentioned earlier, diamond polish and symmetry affect the price of the stone. Higher graded stones are priced significantly higher than those with low grades. 


If you have reached this point of our guide on diamond polish and symmetry, it must have become evident that both are important to a certain degree. Technical terms on diamond polish grades or symmetry are inconsequential if a particular diamond looks appealing to you. It is also better to buy diamonds with negligible flaws visible to the untrained eye, than stones that technically have no flaws but are priced substantially higher.



Add a Comment

Your email address will not be published. Required fields are marked *