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Home >> Diamond Grading >> Diamond Shapes >> Heart Shape >> Depth %

Specific proportions regarding the ideal depth of a heart shaped diamond have not been conclusively determined or published by Gemological Institute of America. Ideal proportion is more difficult to establish in a heart shaped diamond than it is in a round diamond. A round diamond has a consistent pavilion angle that makes ideal proportions easier to establish as a depth percentage. A heart shaped diamond has a pavilion that is made of a variety of angles due to the heart shape variance in length and width. (See Diagram)
Heart Shape Diamond Cut Guide
Specifications for Ideal to Very Fine Cut

Select Emerald Cut Diamonds Within These Ranges

     total depth % ---------- 50% - 60%

     table % ---------------- 50% - 66%

     girdle thickness ---------Very Thin - Thick

     cullet ------------------ None - Medium

     polish ------------------ Excellent - good

     symmetry -------------- Excellent - Good

     flourescence ----------- None - Faint

     Length to width ratio --- .9 - 1.2 to 1

The depth percentage of a heart shaped diamond is determined by dividing the depth measurement by the diameter measurement. Diameter is determined by measuring a heart diamond's width from side to side. The longer length measurement is not taken into consideration when calculating diameter. By viewing a heart shaped diamond from the end view you can see how similar it looks to the proportions of a round diamond. When you view it from the side you can easily see how the pavilion angle is altered due to its longer length. A small amount of light refracts through the pavilion of a heart shaped diamond due to shallower pavilion angles that run towards its pointed long end.

A heart shaped diamond has a unique, beautiful shape that is favored by many women, but a small percentage of brilliance will be sacrificed for the beauty of this unique diamond shape. This brilliance loss is most often seen as a bow tie effect in the center of the diamond. The bow tie effect is a result of a small amount of light leaking through the diamond.

The diagram illustrates a variety of heart shapes with bow tie effects showing resulting changes in appearance due to differing depth percentages and length-to-width ratios. The bow tie effect when seen in a actual heart shaped diamond will be significantly more difficult to recognize than is illustrated in this diagram. This diagram serves only as a guide to approximate bow tie sizes. The bow tie effect is never as clear and distinct as shown in this diagram. It is usually seen as a shadow made up of white and dark reflections.

Gemologists and diamond cutters agree that a small bow tie is considered part of the beauty of this unique and beautiful diamond shape. Many people make the mistake of attempting to select a diamond that displays no bow tie. This diamond will typically have a very deep pavilion which gives the diamond a slightly darker appearance within the entire table facet . This diamond will also be smaller in size compared to better proportioned diamonds of equal carat weight. Diamond cutters and Gemologists agree a heart shaped diamond with a depth percentage between 50% and 60% delivers the greatest amount of brilliance while exhibiting only a small bow tie effect. Heart shaped diamonds below 50% usually produce larger bow tie effects due to reduced pavilion angles. Heart shaped diamonds which measure over 62% generally have a smaller bow tie but appear darker and smaller overall.

When choosing your diamond be aware of its length-to-width ratio. Keep in mind that one heart shaped diamond may exhibit a larger bow tie effect than another heart shaped diamond even though they both have a the same identical weight and depth percentages due to variances in length-to-width ratios. Depth percentage is a percentage of a heart shaped diamond's width; therefore, a longer one carat heart shaped diamond which has a length of 6 millimeters and a width of 5 millimeters with a 65% depth percentage will have a total depth of 3.25 millimeters. A shorter, one carat heart shaped diamond with a length of 5.5 millimeters and a width of 5.5 millimeters with an equal depth percentage of 65% will have a deeper total depth percentage of 3.58 or .32  millimeters deeper than the 5 millimeter wide longer diamond. Heart shaped diamonds of shorter length and greater width display a smaller bow tie due to steeper pavilion angles. It is precisely these  variances that make it difficult to establish specific or exact proportions that identify ideal cut in heart shaped diamonds. Our Certified Gemologist-Appraisers will be happy to help guide you to the most brilliant heart shaped diamond your money can buy.

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