Many diamond shoppers spend a lot of time vetting the color and clarity of the stone they are about to buy but pay less attention to its symmetry. A lot of people don’t even know that such a concept exists or are just vaguely aware of what it means.
What Is Diamond Symmetry?
The diamonds you see in the jewelry store have been cut out of raw stones into shapes whose proportions conform to certain standards in order to make the diamond look as beautiful as possible.
The term “symmetry” refers to how regular the shape of the stone is as well as how proportional and well-aligned the diamond’s facets are.
The more symmetrical a diamond, the more highly its quality is rated.
How Is Symmetry Evaluated?
There are a lot of variables to consider when evaluating a diamond’s symmetry. Some of the factors jewelers consider are:
- How well the diamond’s facets align
- How regular and proportional the shape of the facets is
- Whether the diamond has a perfectly round shape when looked at from above (for round-cut diamonds)
- If the shape of the diamond’s table (its flat top) is proportional and if the table itself is centered
- If the stone’s culet (the pointed bottom) is centered
These are just some of the criteria used to evaluate symmetry.
Jewelers usually look at diamonds under a microscope or jewelry loupe to examine each of these factors and determine how symmetrical the stone is.
It may be interesting for you to learn that diamond cutters often create slightly asymmetrical stones on purpose in order to achieve a desired carat weight or to make some natural imperfections within the diamond less visible.
Why Symmetry Is Important
When it comes to diamond cuts, there is something called “ideal cut”. This is the cut that bends and reflects light in such a way as to maximize the sparkle of the diamond.
Any deviation from this ideal detracts from the stone’s brilliance.
In general, the less symmetrical a diamond, the less sparkle it will exhibit. However, you should keep in mind that in reality, no diamond is perfectly symmetrical.
How Do I Know If a Diamond Is Symmetrical?
There are so many criteria to consider when evaluating symmetry, and it is unrealistic to expect that you would be able to evaluate thoroughly each diamond unless you are a professional jeweler.
Thankfully, if you look at a diamond’s certificate, its symmetry grade will be listed there. The G.I.A. (Gemological Institute of America) uses the following scale: Excellent, Very Good, Good, Fair and Poor.
Generally, if a stone is graded Good or better, it will not have symmetry flaws visible to the naked eye, and for such diamonds, symmetry should not be a concern regardless of the exact grade.
In other words, it is often not worth it to spend additional money to buy a diamond with Excellent or even Very Good symmetry over a stone that is just Good – it is likely that nobody will notice the difference.
When Is Diamond Symmetry Important and When Not?
Symmetry is less important for diamonds of a lower clarity grade – think below VVS1 or VVS2.
A high symmetry grade doesn’t do much to improve the brilliance of such stones as their internal flaws negate the positives of being highly proportional.
For high-clarity stones, you should pay more attention to symmetry. Even if a diamond is nearly flawless, bad symmetry could spoil the effect of almost perfect clarity.
In general, avoid stones whose symmetry is graded Poor.