The term Hearts and Arrows (H&A) refers to round diamonds that have been cut with great precision and possess a high degree of three dimensional symmetry. The diamond’s facets are placed, angled, and aligned so precisely that crisp, symmetrical reflection patterns are visible) with the aid of a simple reflector device. From pavilion view the hearts can be seen, and from table view the arrows are visible.
H&A patterning is visual evidence of exceptional craftsmanship. This level of precision requires more time and skill, as well as the polishing away of more carat weight. Hearts and arrows diamonds are therefore more costly to produce and command a premium in the market.
This article will focus on how H&A patterns are formed from combinations of facet reflections. For a comprehensive understanding of the many aspects associated with these precision cut diamonds, please see our page on hearts and arrows
. For a perspective on what H&A diamonds mean to the consumer please see our page on the benefits of hearts and arrows diamonds
Two Types of Symmetry
The quality of the hearts and arrows pattern is referred to as a measure of a diamond’s ‘optical symmetry’. That is, how well aligned all the facets are in 3D space. Symmetry as graded on a laboratory report is what is known as “meet point” symmetry; the meeting of contiguous facets at the proper points around the diamond. Meet point symmetry can be excellent even when three dimensional alignment is poor. To avoid blurring the distinction between these two types of symmetry it is less confusing to use the term “optical precision” to describe what hearts and arrows tells us about the diamond. Corresponding facets must be precisely the same shape, size, angle and azimuth, in order to align and overlap exactly in three dimensions.
How the Hearts are Formed
The illustration below conveys how each heart is created primarily from two pavilion main facets. The green pavilion main facet shown at seven o'clock is reflected twice to create one half of two separate hearts (green) on the opposite side of the stone. While the yellow pavilion main facet shown at five o'clock is also reflected twice to create one half of two separate hearts (yellow) on the opposing side. The completed single heart shown at 12 o'clock is then a combination of two precisely cut pavilion main facets. It takes a total of 16 pavilion main facet reflections to create the eight basic hearts. It is imperative that all the facets are exactly the same length and shape or the resultant hearts will be deformed and asymmetrical.
The two reflected pavilion main facets creating the lobes of the heart must be further clipped by the combination of table and star facets, which block the lobes making them more resemble the heart shape.
The important chevron patterns shown in pink below the tip of the finished heart are the result of systematically repeating the process of finishing all 24 pavilion facets, including the lower girdle half facets (LGF), with extreme precision.
1. The main pavilion facets outlined in green (1B) are responsible for creating the basic hearts pattern. One full heart with chevron highlighted in red (1A).
2. The main pavilion facet reflects on the opposite side - highlighted in green (2B). Each one creates half of one heart and one half of the chevron below it.
3. It takes two main pavilion facets and their reflections to form a complete heart (3A) and a complete chevron (3B).
4. The pointed top of the heart (4A) is blocked by properly cut upper girdle facets resulting in a properly formed heart (4B).
It is the lower girdle facets that are responsible for separating the chevron from the heart. This reflects the difference between the angles of the main pavilion and lower girdle facets. There must be separation between heart and chevron for true heart patterning.
How the Arrows are Formed
As we have seen, the main pavilion facets are fundamental to the formation of the hearts. They are just as integral to forming the arrows. In fact, the arrow is formed entirely by reflections of the pavilion mains.
In the image above, two different pavilion main facets are shown on the left in pavilion view -one yellow and one green.
Each pavilion main facet when viewed through the table (on right) becomes visible as both the "shaft” of one arrow (A), and is also reflected to the opposite side and appears in the crown forming an arrowhead (B). It is important to note that they become parts of two different completed arrows, underscoring how critical the precision of all the individual pavilion main facets is to a consistent and accurate pattern.
Since the main pavilion facets are the primary drivers of light return, the central role they play in formation of both hearts and arrows patterning is indicative of the significance of a precise H&A pattern. It has a direct bearing on light performance and therefore the overall beauty of the diamond.