The cut of a diamond is one of its most important features, and a stone with an ideal cut usually sells at a premium. But what exactly does “ideal cut” mean, and how can you find a diamond with an ideal cut?
What Does “Ideal Diamond Cut” Mean?
In general, when a diamond’s cut is said to be ideal, this means that the stone has proportions that help it to maximize its brilliance and sparkle.
Although not all cuts are meant to make a diamond look more brilliant (e.g., the emerald cut or the Asscher cut), most of them are created with that goal in mind (such cuts are referred to as “brilliant cuts”).
The term “ideal cut” is used most often when referring to the quality characteristics of the classic round cut, which is also the most popular.
How to Tell If a Diamond’s Cut Is Ideal
The ideal diamond cut is simply a set of proportions used as a benchmark against which diamonds are evaluated. The closer a stone’s actual proportions come to this standard, the closer its cut is said to be to the ideal cut.
So, the best way to see if a diamond’s cut is close to the ideal is to look at its measurements.
Since the round cut is the most popular one, and it is designed to maximize brilliance better than any other cut, the guidelines developed for its ideal proportions are the most detailed.
There are many measurements to consider when evaluating a round diamond’s cut, but here are the most important guidelines that can help you to determine quickly where a stone’s cut stands:
- The diameter of the diamond’s table (the diamond’s top facet) should be 53-57.5% of the diameter of the stone’s girdle (edge).
- The vertical distance from the girdle to the stone’s top facet should be 14.4-16.2% of the girdle’s diameter.
- The vertical distance from the girdle to the bottom point of the diamond should be around 43% of the girdle’s diameter.
If a diamond comes with a grading report issued by a reputable gem lab such as the GIA (Gemological Institute of America) or the AGS (American Gem Society), then this document will contain a grade for the stone’s cut.
Depending on the grading system used by the issuer of the certificate, if the cut of the diamond has proportions equal or very close to the ideal benchmark, it will be graded as Excellent or Ideal (or some other grade will be used).
Looking at a diamond’s grading certificate is usually the quickest and most reliable way to find out the quality of a diamond’s cut.
What about other diamond cuts?
Unlike the classic round cut, most other cuts do not have as detailed, precise, and widely accepted benchmarks against which to measure cut quality. There are guidelines, but they are much looser, and they vary from cut to cut.
What’s more, many grading labs do not grade the cut of nonround diamonds. The best way to evaluate the cut of such stones is to compare them and see which one has more brilliance as well as which diamond looks better (or even bigger) when worn.
How to Buy an Ideal-Cut Diamond
The best way to find a diamond with an ideal cut is to shop at a store that sells certified diamonds with grading reports issued by a reputable body such as the GIA or the AGS.
Look at each diamond’s certificate, and see how the stone’s cut is graded, while also paying attention to what grading scale is used.
Don’t forget to check who issued the certificate – documents issued by nonreputable sources should be viewed with suspicion, and diamonds graded by the vendor itself are likely to have biased (think inflated) quality grades.
In case a stone doesn’t come with a certificate, assess its cut using the proportion guidelines outlined above (for round cuts only). However, we do not recommend that you buy diamonds that do not come with a grading report.
How Important Is It to Buy an Ideal-Cut Diamond?
The closer the cut of a round diamond is to the ideal cut, the higher the stone’s brilliance will be.
Diamonds with poor cuts look less bright and appear lifeless, not to mention that because of the diminished brightness, their flaws and color tints become more visible.
So, it is usually a good idea to pay more money for an ideal cut.
However, going one grade lower than the ideal does not usually result in a visible difference in the appearance of the diamond.
It is not recommended to go much lower, though, so don’t expect much in terms of brilliance from stones at the lower end of the scale.
Where to Buy Diamonds and Diamond Jewelry?
For diamond jewelry, we highly recommend James Allen because it shows real photos and videos for each diamond so you can take a 360-degree look at any stone before buying it.
For colored diamonds, we recommend Leibish & Co., which specializes in fancy color diamonds (use code JewelryNotes200 at checkout to get a 5% discount).