Hearts and Arrows Diamonds: Everything You Need To Know


A Hearts and Arrows diamond is a round brilliant diamond cut to show crisp 3D optical precision, also called optical symmetry. When a round brilliant diamond has proven ideal light performance and is further fine-tuned to show a crisp pattern of “hearts and arrows,” it belongs to an extremely rare subset of “Super Ideal” diamonds.

Before going on: Read Diamond 101: 4Cs and More

Basics-1 | Hearts and Arrows Diamond Described

A Hearts and Arrows diamond, also called “H&A,” is cut so that its facet reflections precisely overlap when seen in the structured light environment of a hearts and arrows viewer.

Girl looking through a hearts and arrows diamond viewer

The kaleidoscopic pattern seen face-down in the pavilion resembles “hearts,” and the pattern seen face-up in the crown resembles “arrows.” Hearts and arrows optical precision is usually associated with Ideal or Excellent cuts of superior quality.

Hearts and Arrows Diamond Chart

Hearts seen in pavilion and arrows seen in crown

What causes the patterns to appear?

Light entering the viewer from above remains white. Light coming from the sides is colored by filament paper (typically red, blue or purple). This creates the structured lighting environment where the diamond’s primary facet reflections stand out as white against a darker background for analysis.

Basics-2 | Are Hearts and Arrows diamonds all “Super Ideal?”

Not necessarily. Only 3-5% of all diamonds graded ‘Excellent’ or ‘Ideal’ fall into the Super Ideal subset (PriceScope estimate), making them extremely rare. To meet PriceScope’s definition of Super Ideal, a diamond must be cut within a small range of acknowledged “ideal” proportions. Beyond those basic proportions, the internal reflections must be further fine-tuned to display crisp 3D optical precision (aka Hearts & Arrows) in a specialized viewer. Top Super Ideal diamonds are not casually or accidentally made.

Basics-3 | Are all Hearts and Arrows diamonds the same?

No. A variety of different standards and definitions exist. Some are stricter than others. Many diamonds produced in modern times mimic hearts and arrows patterns, simply from good tooling. These diamonds are sometimes nicknamed “Happy Accident” H&A diamonds. They do not have the distinctive crispness and precision of diamonds purposely refined to show the highest levels of 3D Optical Precision.

Optical Precision Example Chart

H&A diamonds examples from GCAL
Courtesy of GCAL

Intermediate Hearts and Arrows


Analysis-1 | Do Hearts and Arrows cost more to produce?

Yes, primarily due to weight loss incurred in refinement. Achieving strong hearts and arrows optical precision is an exacting process. All facets must be aligned in both angle and orientation in a three-dimensional way.

The three examples below are hypothetically polished from the same starting rough crystal (the dark blue outline). They have identical color and clarity, and all received the “Excellent” cut grade. The specimen which meets PriceScope’s definition of Super Ideal cost more to produce because it required more hours, better tools and, most notably, more weight loss from the original diamond crystal.

Three Common Round Brilliant Subsets

Examples of steep deep, PriceScope ideal and super-ideal yield from diamond rough

The payoff is the potential to optimize light performance through cut-consistency, achieving top brightness when paired with proper angles for light return, and top fire by optimizing the size of the diamond’s internal reflections, or compound mirrors, promoting more visible dispersion.

Analysis-2 | What laboratories grade H&A diamonds?

The only top-tier laboratories which apply grading standards for the hearts and arrows diamond are IGI and GCAL.

    • IGI is highly regarded for their hearts and arrows diamond grading across China and India.
    • GCAL is best known for in-depth cut analysis and high-quality standardized H&A photo and videos.

Beware hearts and arrows laser inscriptions

When submitting a diamond, the producer can request for anything to be inscribed on that diamond. For example, the producer could ask for “D-Flawless” to be inscribed on a J-SI1 diamond and that inscription would then become listed in the comments section. Therefore, when you see the notation that a diamond has “Hearts and Arrows” or “H&A” inscribed on its girdle issued by a laboratory that does not grade hearts and arrows, be cautious. Such an inscription does not mean a hearts and arrows standard was passed. It only means the producer requested for those characters to be inscribed when the diamond was submitted to the lab.

Hearts and Arrows Doesn’t mean Top Light Performance

Because of a diamond’s refractive index, the pavilion and crown need to be cut at angles which complement each other and return light to the viewers’ eyes. No matter how crisp the hearts and arrows optical precision may be, if the primary angles don’t complement each other the diamond begins to leak light, which affects light return. Hearts and arrows diamonds need separate assessment for light return. A hearts and arrows viewer doesn’t give any indication of light performance.

AGS Ideal does not mean Hearts and Arrows

Just because a diamond is cut to have AGS ideal performance does not mean that it will exhibit a crisp hearts and arrows pattern. Here is an example of a diamond which has AGS Ideal Light Performance, but would be completely unacceptable by any meaningful hearts and arrows standard:

AGS ideal does not mean H&A

Lab Graded Symmetry is not H&A Optical Precision

The labs grade symmetry according to meet point symmetry on the surface of the diamond only. The formation of hearts and arrows involves facet polishing on the X,Y, and Z-axis. This is not assessed as any part of laboratory symmetry grading.

GIA and AGS do not grade Hearts and Arrows

Since GIA and AGS do not currently grade hearts and arrows, the assessment of hearts and arrows quality in a GIA or AGS graded diamond requires separate analysis of that diamond’s 3D optical precision.

Analysis-3 | Analyzing Hearts and Arrows

If you can’t examine the diamond in a hearts and arrows viewer yourself, then hearts and arrows photos made with a camera looking into the viewer are the best way to judge the degree of precision and accuracy to which the optical precision was executed.

Sellers specializing in hearts and arrows diamond reliably provide these images.

Hearts and Arrows Photos

Actual photos of hearts and arrows diamonds

Computer Generated Images (CGI)

Some diamond industry software applications such as DiamCalc and the AGS light performance software are capable of generating photorealistic diamond images and videos. These computer generated renderings include performance scope (i.e. Ideal-Scope, ASET) simulations and optical precision scope (i.e. Hearts and Arrows) simulations.

PriceScope Pointer: Before using computer generated images (CGI) for analysis it’s critical to know whether the images were generated by manual input or from a mechanical 3D scan of the diamond. 

Manual Input CGI (not useful)

The easiest way to produce computer-generated images (CGI) is to manually enter data from a grading report into the software. This is not useful and is misleading. When only broad average numbers are entered the software draws perfect 3D optical precision (which doesn’t exist in nature) and will produce images based on a theoretically perfect, unrealistic diamond wireframe.

Manual Input CGI of hearts and arrows diamonds

The perfect optical precision circled above is a misrepresentation. It’s impossible to know how close or far away from the actual diamond’s hearts and arrows patterns these CGI may be. The data on lab reports is also averaged and rounded, which adds a further margin of error.

3D Scan CGI (uses actual mechanical scan)

The only representative CGI are those made from a mechanical 3D scan of the actual diamond, executed with a non-contact diamond scanner such as Sarine or OGI. The hearts and arrows images generated by the software may be very close to actual hearts and arrows photos, depending on whether the scan was well-executed or not. They are still not as decisive as actual photos or in-person viewing.

3D Scan CGI of hearts and arrows

Because computer-generated images have the appearance of actual photos, it is important to verify with the seller if the imagery they are providing is actual photography of the diamond, or CGI. If the images are CGI, verify that the seller secured a mechanical 3D scan of the actual diamond.

PriceScope Pointer: Whether intentional or by accident, some diamond sellers provide Hearts and Arrows, Ideal-Scope and ASET simulations from manual input CGI. Those images do not represent the subject diamond and give a false positive impression. Be sure a mechanical 3D scan was used. You might also ask the seller to send you the 3D scan. Common file formats are .SRN .STL .DMC .ASC and DXF.

AGS Light Performance Maps

AGS Platinum Reports may have diamond specific renderings of ASET maps. When these are printed on “dual light map” or “triple light map” certificates, as seen below, an ASET image is rendered for the bottom of the diamond. The only purpose of that rendering is to simulate the hearts pattern in order to communicate 3D optical precision. Because these images are made from an actual 3D scan they can be very representative. They are not as decisive as actual photos or in-person viewing.

Hearts and arrows diamonds: AGS renderings of crown and pavilion ASET

Advanced Hearts and Arrows Diamond


Evaluation-1 | History and Symbolism

In the 1980s, Japanese diamond cutters were first to produce round brilliant diamonds cut so precisely that their facet reflections overlapped in 3D space, creating consistently-shaped patterns when seen through reflecting viewers.

Those polishers used “secret recipes” to create the pattern of hearts – a combination of reflections circled in red below – when looking down on the pavilion and arrows – reflections of the eight pavilion-main facets seen through table and bezels – in the crown, when viewed in the table-up position.

Hearts and arrows diamonds: elemental formation

The precision and crispness of the patterns relies on precise angles in combination with specific facet length, width and azimuth. The techniques of the first producers spread to other cutting houses and hearts and arrows diamonds began appearing on several continents by the mid-1990s.


The eight uniform patterns seen in the top and bottom of hearts and arrows diamonds have a historical association with good fortune and spiritualism. The number eight is considered lucky in Asian culture. The arrow pattern has been compared to the Octagram of the I Ching, the Rinbo of Buddhist law and the eight-spoked wheel of Dharma, associated with spiritual perfection in the Buddhist faith.

H&A diamonds - Eight spoked wheel

Regardless of spiritual belief, the achievement of the perfect hearts and arrows pattern, painstakingly cut into the world’s hardest substance, can be appreciated by any admirer. In its most fundamental form, it symbolizes the diamond cutter’s quest for perfection and the ultimate beauty of a diamond.

Evaluation-2 | H&A Cutting Process


The rough diamond is prepared and sawed. Depending on the grain of the rough, this can happen in different ways. The flat, sawed surface will ultimately become the diamond’s table. The stone is then “bruted” or girdled (made round).

Hearts and arrows diamond - Diamond sawing


Next, the stone is “blocked:” first in four, then in eight.  Four facets are polished on the top, forming the first crown main facets, next to the flat table facet.

Hearts and arrows - Blocking in four on crown

Four main facets are also polished on the bottom, forming the first pavilion main facets. These ideally come to an exact point. The stone is now blocked in four.

Hearts and arrows diamonds: Blocking in four on pavilion

The remaining facets are then polished on the top, for a total of eight main crown facets adjacent to the table, as well as the bottom, for a total of eight main pavilion facets. With these primary 17 facets in place (1 table facet, 8 crown facets and 8 pavilion facets) the diamond is now blocked in eight.

Blocking in eight on crown and pavilion


With the main facets in place, the upper and lower halves and stars are polished on the stone.

Blocking and brillianteering

How the Hearts and Arrows are Formed

Here is a view of how the hearts and arrows are formed during the cutting process, seen through a hearts and arrows diamond viewer.

Formation steps in hearts and arrows diamond viewer

Hearts Formation

How the hearts are formed in a diamond

  1. The main pavilion facets are outlined and one heart is highlighted in red.
  2. The main pavilion facet reflects on the opposite side.
  3. It takes a total of six facets to create one heart: Four facets create the main body (and one arrowhead on the pavilion) and an additional two upper half facets finish up and square off the tips of the “rabbit ears” of the heart.
  4. Figure A shows the heart formed only by the four main facets, without the upper half facets in place. Figure B shows the complete heart, with the two upper girdle facets in place. Note the squared-off heart shape.

Arrows Formation

Just as the main pavilion facets are responsible for the formation of the hearts, they are also key in forming the arrows pattern: The shaft of the arrow is formed when one main pavilion facet reflects on the opposite main pavilion facet. The main crown facet allows a different view of the reflected main pavilion facet thereby forming the arrowhead.

How the arrows are formed in a diamond

Evaluation-3 | Grading Guidelines

There are different approaches to the assessment of hearts and arrows optical precision. The long-standing guidelines below were developed and carried forward by hearts and arrows subject-matter experts and have proven popular among enthusiasts in the PriceScope community.

Grading hearts and arrows requires in-person viewing. Confirmation of quality is practical with high quality photos made in a hearts and arrows viewer. CGI cannot be used for meaningful hearts and arrows assessment.

Grading the Hearts

  • Eight equal uniformed symmetrical hearts.
  • Eight distinct symmetrical hearts that separate from the arrowheads above. If this is correct, check the following.
  • Check if the hearts are split and measure length of the heart, then the length of the split.
  • Calculate the % of the length split – if it is greater than 8% and there are more than two of them, it’s not a classic heart shape.


First: Check to have eight equal hearts and arrow heads. They must be equal in size and shape, as seen in the “Acceptable” picture below. In the “Fails” picture, you can see the hearts are not equal in size and there is an unacceptable split length in the cleft.

In A1, A2, and A3 the heart is well-defined; the gaps between the arrowheads are distinct and clear, and the split at A3 is minimal versus F1, F2, and especially F3.

Grading the hearts diagram 1

Next: Calculating whether cleft splits are acceptable, you can measure heart-length as shown X to Y in figure 1a. Any splits in the cleft can be no longer than 8% of that calculated heart-length. In addition, the point of the heart must separate from the chevron above, as seen near the Xs.

Grading the hearts diagram 2

Unacceptable Examples

Here are examples of hearts that are not acceptable, simply because they are not equal and homogenous, and the arrowhead and hearts blend together in some cases.

Grading the hearts diagram 3

Grading The Arrows

  • Each arrow must be clearly visible with a shaft and an arrow head.
  • The eight arrows shafts as well as heads have to be straight and in the right position.
  • The eight arrow points must meet the girdle.
  • There must be total uniformity and balance.

At a casual glance, the poorly-formed arrows are not immediately seen as unacceptable. Look closely: not all the arrowheads reach the girdle and the shafts do not line up straight with the arrowhead.

H&A diamond: Grading the arrows

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