Hearts & Arrows Diamond & What Jewellers Usually Tell You

You have read about Hearts & Arrows diamond. Many jewellers you have met may either:
  1. Downplay the importance of Hearts & Arrows.
  2. There is no visible benefit of a Hearts & Arrows diamond.
  3. Tell you that Hearts & Arrows are always there if it is a round brilliant cut.

I am not a technical person at this, so I will put it in my own layman understanding explaining why what they said are wrong.

Hearts & Arrows offers great symmetry precision to the diamond. Surely you may think that within such a small stone, the disorientation is not noticeable and the performance is more or less the same. Yes, you are right that you probably can't noticed the disorientation without close inspection, however, for performance, you have to know diamond is reflecting light, just like a mirror, so imagine you have one a light source pointing at one mirror, and the mirror then reflects the light to another mirror that is aligned correctly and so on. Keep going this until all the mirrors are reflecting light, and thus achieving maximum beauty in terms of light performance. Now, imagine some mirrors are disoriented and only reflect the light partially, so what will you get? Lower light performance, right? So that's why it is best to have the whole diamond to be as symmetrical as possible in order to achieve the best performance, and this is the benefit of Hearts & Arrows.

Now, the above is just part of the puzzle to get great performance. We move on to proportions.

In science, we know that a certain value will be a critical point for something - For example, for water to boil, it will be 100 degree celsius and for it to freeze, it will be 0 degree celsius. This concept is also applicable to light, when it is travelling to and fro within the diamond, busy reflecting and refracting the light. It is very well proven that certain angles are critical tipping point and certain angles will give the best performance. For instance, I won't buy a diamond a 36 degree crown angle because I know that the light return will be much lesser than a diamond with 35 degree crown angle. Same concept applies to pavilion, I won't buy a diamond that is beyond 41.2 because that is a critical tipping point whereby light does not fully strike off the pavilion. (Reference: http://niceice.com/diamond-grading-101/obstruction-light-diamonds/) Now, that being said, at 41.2, things may go either way, so it will be best to stay below that range. The recommended range is the middle range whereby performance will be the safest - 40.6 to 40.9 pavilion degree angle.

So, with great optical precision and great proportions combination, what you will get is an ideal amount of light reflecting and refracting at the best angle possible to maximize the beauty of the whole diamond. Missing out either one of them, and you won't be getting the best possible performance in terms of brilliance, dispersion, and scintillation.

For your info, there can be Hearts & Arrows diamond that returns poor amount of light because that diamond has very steep crown angle. For instance, this diamond: https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3855514.htm?a_aid=myengringexp

0.7 F VS2 Premium Select GIA-2185393735 H&A

Can you see how beautiful the Hearts & Arrows is? I do notice that the 2 hearts between 6 o'clock and 9 o'clock position looks slightly smaller, but that is within an acceptable range in terms of percentage. Therefore, this diamond is a real Hearts & Arrows diamond. In fact, its precision is pretty top-notch as far as I am concerned.

Now, let's look at both IdealScope and ASET images:

0.7 F VS2 Premium Select GIA-2185393735 IdealScope

0.7 F VS2 Premium Select GIA-2185393735 ASET
So, what does this tell you? Light leakage. This diamond will certainly perform under spotlight condition, but will be dead under normal fluorescent light. This is due to its very steep angle at 36.5 degree crown angle. So it is advisable to avoid such crown angle. Some cutters may really cut it for the fire it produces under spotlight, but personally, I think most cutters will cut such steep angles if they want to retain the carat weight of the diamond, and they are willing to do it at the expense of the overall diamond beauty.

That being said, have you ever got the chance to look at a diamond that claims to be Hearts & Arrows? If you said yes, did they show you the hearts? I guess probably not, because based my own experience, the sales person will tell you that the stone is mounted. Fair enough, but despite the arrows can be very good, we can't guarantee that the hearts can be as good. This is certainly different that what some salesperson will usually claim: "Perfect/very good arrows mean perfect/very good hearts".

Update 20 November 2017
I updated the statement:

Perfect arrows to Perfect/very good arrows
Perfect hearts to Perfect/very good hearts

Reason is that what I am comparing here, some vendors will claim this to be "perfect arrows", which is actually fair enough because they are in fact very good arrows.


Below are some of the diamonds with very good arrows, but with inconsistent hearts.

Here is the first diamond: https://enchanteddiamonds.com/diamonds/view/R552-0628956Z2?
GIA-2161035626
The arrows are good, with some small penalty for the arrows at 11 o'clock. But overall, the diamond's arrows are pretty much well-aligned.

GIA-2161035626
This is what you see when you see through the diamond from the top through a H&A scope.

GIA-2161035626
Now, this is what I mean good arrows, but inconsistent hearts.
Here is another one: https://enchanteddiamonds.com/diamonds/view/R100-5Z6082690?
GIA-6242735300
The arrows are pretty much well-aligned as well, with some penalty for the arrow at 1 o'clock position 6 o'clock position, and 11 o'clock position.
GIA-6242735300
This is what you see when you see through the diamond from the top through a H&A scope.

GIA-6242735300
Oh my, what happened to the hearts?
The example I provided above have some of the best arrows around, there could be better ones, but there are more worse ones. And despite being good arrows, the hearts does not share the same fate. Why is this so? This is because most likely because of light obstruction.

Observe the below picture:
GIA-2161035626
GIA-6242735300
Referring to this post - http://niceice.com/diamond-grading-101/obstruction-light-diamonds/ by Todd Gray:
Obstruction can result from slight differences in the size, shape, or alignment and indexing of the facets. Diamonds that exhibit crisp and complete patterns of hearts and arrows tend to exhibit very little obstruction. Whereas diamonds with a lot of obstruction almost always exhibit irregular patterns of hearts and arrows.
Therefore, as you can see, we have to be careful with a the claim that perfect arrows mean perfect hearts because perfect arrows is just one of the main criteria to achieve perfect hearts, and not the only one. Do request for the actual diamond image and check on the image and see if you can find any light obstruction.

Also, both of these diamonds score a 100% on Enchanted Cut Score. Therefore, this means good cut score does not necessarily translate to good hearts / good optical precision as well.

So now, if you ask me - If there is not light obstruction, and the arrows are perfect, will the hearts be perfect? My answer is "As long as the lower girdle facets' percentage is not too big and being kept at max 80%, there will not be any clefts (or obvious ones) in the hearts of the diamond, and hence it is very likely that this diamond has perfect hearts. This is based on my observation on Enchanted Diamonds after browsing through their diamond inventory and filter out those diamonds that provide images.

Despite all the cons above, I am actually okay if the price charged is relatively cheaper compared to a real super ideal diamond, but if the price is as close, then it is not worth it.

I hope this article shed some light on why the images such as Hearts & Arrows images are important to proof that a particular diamond has great optical precision.

For those who are on the hunt for the perfect diamond, all the best and good luck. If you need help, you may PM me on Lowyat forum or reply on the "Brides & Grooms" tab. My username is "kambingkoh". Alternatively, you can also drop me an email at blogger.yang85 at gmail.com.
November 16, 2017
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