What Are the Proportions of an Ideal Cut Diamond?

Formed over billions of years and born of tremendous pressure, diamonds are the hardest substance known to man and have captivated the world for centuries. But, as you know, not all diamonds are created (or cut) equal. When it comes to the cream of the crop, the best of the best, and the most elite in a superb class, ideal cut diamonds emerge as the finest specimens. With maximum brilliance and sparkle, these stones literally set the bar: they are the standard against which all other diamonds are graded. Understanding ideal cut diamond dimensions is important in maximizing not only the beauty of your pieces but your profitability.

An ideal cut diamond casting a long shadow

What Is an Ideal Cut?

Diamond cutters must work with precision and meticulous care in order to maximize visual performance while minimizing carat weight. Ideal cut diamond proportions allow the stone to retain and reflect as much light as possible, which produces the brilliance and sparkle we all love. An ideal cut diamond may be a round, brilliant, or princess cut. 

The ideal cut is dependent upon perfect proportions and symmetry: these must be precise. The further a diamond’s dimensions are from the “ideal” measurements, the more leakage there is. That is, the light that enters the diamond is not reflected or refracted; it simply leaks out and results in a dull appearance. On the other hand, an ideal cut appears to be lit from within; it is stunning.

Ideal Cut Diamond Dimensions

In the US, ideal cut diamond dimensions are determined by the American Gem Society Laboratory (AGSL). Even minute imperfections and miscalculations in cutting are unacceptable. AGSL’s standards:

Measurement

What Is It?

Ideal Cut Dimensions

Table Diameter

Percentage of the table diameter versus the diameter of the girdle. Thus, an ideal cut’s table diameter is 53% - 57.5% of the girdle’s diameter

53% - 57.5%

Crown Height: 14.4% - 16.2%

Crown height is the proportion of the crown height to the girdle diameter)

Crown Height: 14.4% - 16.2%

Crown Angle

Angle of the diamond between the table and girdle

33 - 35 degrees

Pavilion Depth

Vertical distance from the girdle to the bottom of the stone

42.5% - 43.5%

Pavilion Angle

Angle of the diamond between the pavilion and the girdle 

40.5 - 41 degrees 

GIrdle Edge

Very thin girdles leave stones vulnerable to chipping; extremely thick girdles make diamonds appear smaller; an ideal cut is thin, medium

0.7% - 2.9%

Total Depth

Distance from table to cutlet - it is the physical depth of a diamond divided by its width

59.5% - 62.9%

Ideal cut diamonds represent the finest examples of cutting and polishing in the world, the result of phenomenal skill, experience, and meticulous care. These diamonds are highly sought-after, and their relative rarity elevates the price point consumers are willing to pay. In the diamond world, ideal cuts are the headliners - and the showstoppers. 

Cut is arguably the most important of the 4Cs, and as we can see with ideal cut diamonds, it has a significant impact on brilliance, sparkle, quality, and, of course, demand for pieces that incorporate these stones. 

K Rosengart’s cutting and polishing experts specialize in ideal cut melee diamonds. Add beauty, elegance, sparkle, and value to your pieces - and dazzle your customers. Get in touch to see how our team can help your business. 

 

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