Formation and Grading of Hearts and Arrows Diamonds

The research about Hearts and Arrows was started in late 1997 by Brian Gavin together with his father Benjamin Gavin. This research ran over a period of two years which ultimately perfected the combination of angles and percentages for A CUT ABOVE to deliver the most optically balanced diamond today. These years of hands on development led to my presenting the below tutorial in Moscow, Russia, April 23-26, 2004 at the First International Diamond Cut Conference.

Consumers today have become more and more educated and demand perfection in cutting as they do in any other high end consumer product today. They want to know that they have a finely manufactured stone. The advent of the Heart and Arrow effect in the market became a tool for consumers to see perfection in optical symmetry. Since optical symmetry is difficult to quantify because of the variations between each cutter and each stone, criteria need to be standardized for consumers to avoid discrepancies. Therefore just as the Labs grade Color, Clarity and Cut, they should grade the Hearts and Arrows too. Diamond Manufacturers should be rewarded for their excellence in producing an optical symmetrical stone and consumers need to be able to purchase assuredly and with comfort. I will explain what causes the Hearts and Arrows effect and how I feel that they should be graded. The perfectly shaped hearts are formed when the main pavilion facets are cut at the correct angles and polished with such perfection in symmetry that their reflection results in a perfect heart pattern. Once the perfect heart pattern has been attained, the perfect arrow pattern in the crown results.


How the Hearts Patterning Are Formed
The above show, in sequence, how the main pavilion angles reflect to create the heart pattern.

One pavilion facet creates two opposite sides of a heart.

Two Pavilion facets create 1 heart and 2 single sides of the next heart and so on until all the hearts are complete.

Hearts Formation
The picture above shows the main pavilion facets outlined and one heart highlighted in red
More detail Of Hearts Formation
The main pavilion facet reflects on the opposite side and the lower girdle half separates the arrowhead above the heart
Completion of heart when Star facet is in place
It takes a total of 5 different facets to work in harmony to create 1 Heart, = ( 2 main pavilion facets and 2 Lower girdle facets and 1 Star facet crown .) See pic.1: without Star facets and pic.2: with the Star facet in place. Note the squared off heart shape.
Hearts with and without upper girdle facet

If the physical symmetry is out the slightest, the optical symmetry will be affected. The optical symmetry will clearly show the physical symmetry being in or out of perfect harmony. The lack of optical symmetry will be seen very clearly when viewing the diamond through a H&A scope. In forming the arrows it is easier to camouflage errors in the formation of the arrows, as there are less facets to align but it is impossible to hide any inconsistencies in the heart pattern, whereas in the hearts there are 5 facets that complete each heart shape, in addition the upper girdle facets complete the patterning around the outside circle of the pavilion and the slightest deviation is easily noticed.Pic 3: without upper girdle facets and Pic 4: with upper girdle facets

True Hearts
True Hearts

The Arrow Effect

The eight main pavilion facets also cause the Arrow effect