How are Hearts and Arrows Diamonds Graded?

Round diamonds crafted with high precision within a narrow range of desirable proportions and achieving a high degree of three dimensional symmetry are referred to as Hearts and Arrows or H&A. The diamond’s facets are placed, angled, and aligned so precisely that crisp, symmetrical reflection patterns are visible from both pavilion (hearts) and table view (arrows), with the aid of a special reflector device.

Evaluating H&A patterning is a means of understanding the skill and care that went into crafting the diamond. It also reveals important information related to light performance. The level of precision required for an accurate pattern to be exhibited 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. When other conditions are met, precision cutting results in diamonds with extraordinary beauty.

But not all diamonds marketed as Hearts and Arrows are equal. Because there is no universally agreed standard, many merchants take wide liberties in assigning the H&A designation to their diamonds. It is therefore necessary to understand what it takes to make perfect hearts and arrows and how deviations from top precision can be detected.

This article will discuss hearts and arrows diamond grading, as well as how these patterns are actually formed via specific 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. To learn what H&A diamonds mean in terms of beauty and value to the consumer please see our page on the benefits of hearts and arrows diamonds.

It should be noted that neither of the top two grading labs directly grade hearts and arrows patterning. Facet precision is indirectly taken into account in the AGSL light performance grading system, and pavilion view ASET images printed on AGSL dual light map reports is designed to show patterning.

To be considered a true super ideal, a diamond must have a near perfect hearts and arrows pattern. The following grading standard is used by Whiteflash in determining qualification for our A CUT ABOVE® super ideal brand.

The basics – what to look for:

• Hearts should be uniform in shape and equal in size.
• All hearts should have clean separation from the chevrons pointing at the culet.
• The clefts between lobes of the heart should have minimal splitting.
• The lobes of the hearts should be squared off by the crown facets.

1. In assessing uniformity of hearts, no heart should be more than 5% larger or smaller than the average size of all hearts, otherwise the pattern fails to make the criteria.

2. In assessing the clefts, any splitting present should not exceed of 8%. That is, the ratio of length from the beginning of the split (Z) to end of split (Y) relative to the length from beginning of the split (Z) to tip of the heart (X).

Here are examples of hearts that do not meet the criteria for various reasons, some more obvious than others.

1. Each of the eight arrows must be clearly visible with a shaft and arrow head.

2. All arrows and arrow heads must be in alignment.

3. The 8 points of the arrowheads must extend to the girdle.

The Hearts and Arrow pattern is possible in any round brilliant, but if the diamond has not been crafted with precision alignment in three dimensions (optical precision), and proportioned within a rather narrow range of parameters, it will not exhibit a true and accurate hearts and arrows pattern.

Here is a comparative study of patterning. All the diamonds depicted here are 0.90 ct in weight and range from 0 to 7 on the AGS scale according to cut parameters.

A diamond can be an AGS Ideal without being H&A. And a diamond can be H&A without being Ideal.

Even when a diamond is cut within AGS Ideal proportion and receives an AGS 0 cut grade, it can fail to meet hearts and arrows criteria. Although an AGS 0 light performance-based certificate is the strictest cut standard of any major laboratory, AGS0 combined with H&A precision is another level altogether- the true super ideal.

The images below are all AGS0 diamonds and show various deficits in patterning and therefore precision. Only the image on the far right has a true and accurate H&A pattern and can be legitimately deemed a “super ideal”.

Whiteflash is a specialist in precision cut diamonds with more Ideal H&A diamonds in-stock than any other retailer in the market. We have three in-house categories - A CUT ABOVE®, Expert Selection, and Premium Select. All diamonds in these categories are in stock and available for immediate delivery and posted to the website with a full array of diagnostics and light performance imagery.

Our A CUT ABOVE® brand is a true super ideal and is considered by experts to be among the finest diamonds on the market. In order to achieve this brand a diamond must be an AGS Ideal and have near perfect hearts and arrows patterning, in addition to passing a number of other important specifications and qualifications. Simply put, the “Best of the Best”.

The Expert Selection brand consists of AGS Ideal rounds that feature H&A patterning within the range offered by the better retailers who are supporting their claims with H&A imagery. There is more variability in this range and Expert Selection diamonds are not required to conform to all the stringent requirements of A CUT ABOVE®, although many of them do exhibit perfect H&A patterns.

Our Premium Select category features GIA Triple Excellent diamonds with H&A patterning. While the top cut category in the GIA system is quite broad and forgiving, Premium Select diamonds represent the best of GIA rounds – those with optical precision and proven light performance.

As discussed above, in order for a diamond to exhibit an accurate hearts and arrows pattern, it must be cut with intentional precision. The facets must be aligned so accurately in three dimensions that reflection from multiple facets can combine to create a consistent pattern all the way around the diamond. From pavilion view the hearts can be seen, and from table view the arrows are visible with the aid of special viewers and computer simulations.

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.

From a light performance perspective, hearts and arrows patterning provides visual evidence that the proportioning of the diamond and alignment of its corresponding facets in three dimensional space provides for efficient channeling of light into and within the diamond and back to the eye of the observer. If a diamond is thought of as a miniature sculpture consisting of a system of tiny mirrors, H&A patterning demonstrates that the system is finely tuned for optimal performance.

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.

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.

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.

Now that you know the importance of precision cutting and how hearts and arrows are graded and formed, you are an educated shopper. So go ahead, get out there and find your perfect diamond!