Diamond Guide: The Ideal Crown Angle and Pavilion Depth
The crown angle, pavilion depth and angle of a diamond can all make a big difference in the end result of a diamond’s appearance, creating either a sparkling wonder or a dull stone.
In this guide we explain the different angles and depths, as well as how to calculate them. We also provide a handy table with the ideal round cut diamond proportions to help you find the perfect diamond.
Crown Angle
The top part of the diamond is called the crown, below the flat top table, and ‘crowning’ the pavilion cone. But the actual crown angle of a diamond refers to the degree of separation between the diamond’s girdle and table.
How important is crown angle?
The crown angle plays a major role in a diamond’s face-up appearance. When combined with ideal overall proportions, an ideal crown angle disperses maximum light, also referred to as a diamond’s fire. This makes the crown angle an extremely important aspect in a diamond’s proportions.
What is the Best Crown Angle for a Diamond?
The expert opinion is that the best crown angle is between 32-35 degrees. When the crown angle of diamond is smaller than 32 degrees it is called a spread-cut, creating a foggy appearance in the diamond. This is caused by an overly large table area and a too thin girdle, which also causes the edges to be unprotected.
How to Calculate the Crown Angle of a Diamond
- Divide the table of the diamond by 100.
- Subtract your answer from 1.
- Multiply that answer by 50.
- Divide the crown depth by said answer above.
- Using a scientific calculator, press the Tan – 1 button.
- The answer given will be the actual crown angle expressed in degrees.
Pavilion Depth
The pavilion of a diamond refers to the lower part or the ‘V’ shape of a diamond, it acts as a mirror to reflect light back through the top crown and table to the viewer.
What is the pavilion depth on a diamond?
In its simplest sense, the pavilion depth is the distance from the flat top table to the culet, or bottom point of the cone, of a diamond.
Impact of Pavilion Depth
Pavilion depth contributes to both fire and brilliance in a diamond, it is also a way to increase the size of a modest diamond’s appearance. A shallower depth helps the diamond appear larger when viewed from above, although if it’s too shallow the diamond will appear dull and muted.
The pavilion depth is expressed as a percentage of average girdle diameter, and it can be judged visually, or measured and calculated.
How to Calculate the Pavilion Depth Percentage
- Divide the pavilion depth by the average girdle diameter
- Multiply that answer by 100
- The answer will be the pavilion depth percentage.
Pavilion Angle
Some people like to use the pavilion angle instead of pavilion depth percentage when they are evaluating a diamond’s proportions. Really, they are just two different ways of looking at the same aspect. The steeper the angle, the greater the depth percentage.
The pavilion angle creates that sparkling, eye-catching appearance revered in diamonds. The angle refracts light from one side of the diamond to another before reflecting outwards, creating a gorgeous prism of light. Diamonds that don’t possess the ideal pavilion angles, if they are perhaps too deep or too shallow, will be sorely lacking in beauty.
How To Calculate The Pavilion Angle of a Diamond
- Determine the pavilion depth of the diamond and enter the answer in a scientific calculator
- Then divide the answer by 50
- Next, press the Tan – 1 button on your scientific calculator.
- The answer will be the actual pavilion angle expressed in degrees.
Ideal Diamond Proportions for Round Cut Diamonds
|
Depth Percentage |
59% to 62.6% |
|---|---|
|
Depth Percentage |
59% to 62.6% |
|
Pavilion Angle |
40.6% to 41% |
|
Crown Angle |
34% to 35% |
|
Girdle Thickness |
Thin to Slightly Thick |
|
Culet |
None to Pointed |
