“I’m shopping for a diamond engagement ring and am trying to determine the difference between Hearts and Arrows vs round brilliant cut diamonds. My local jeweler told me that all round brilliant cut diamonds exhibit hearts and arrows patterns. However, that does not seem to correlate with what I’ve read on your site and others. What are the differences between round and hearts and arrows cut diamonds? And are there any differences that I’ll be able to see with just my eyes under every day viewing conditions?”
Round Brilliant vs Hearts and Arrows cut diamonds:
The modern round brilliant cut diamond has 57 facets, which rises to 58 facets if you include the bottom culet. Hearts and arrows round brilliant cut diamonds, also feature 58 facets. The factors that dictate whether a round brilliant cut diamond will exhibit a hearts and arrows pattern, are a combination of proportions and optical precision.
Optical precision is the consistency of facet shape, and size; but it also requires extreme precision with regards to the alignment of the facets, as they are indexed, or polished upon the surface of the diamond.
In order to create a crisp and complete pattern of hearts and arrows, the diamond cutter must actually be skilled enough to address this issue from the perspective of 360 degrees. When this is accomplished, light will reflect off the pavilion main facets, and reflect across the diamond in two sections, which reflect off of adjoining lower girdle facets. Thus, each heart is actually the sum of two halves of the light being reflected. (see image above).
GIA Excellent vs Hearts & Arrows cut diamonds:
If the statement made by your local jeweler were correct, then all round brilliant cut diamonds should exhibit crisp and complete patterns of hearts and arrows. Proving that statement is easy enough for your jeweler to do, all they need to do is show you any of their round brilliant cut diamonds under a hearts and arrows viewer.
Obviously, they didn’t attempt to support that (absurd) claim, or you wouldn’t be trying to figure this out on your own. So, here’s a photograph of a GIA Excellent round brilliant cut diamond, as seen through a hearts and arrows scope.
The shape of this diamond is obviously round, and it does exhibit a pattern of some sort. However, I’d argue that what we’re seeing here look more like lawn darts than hearts. Notice the lack of symmetry, and how each lawn dart is a slightly different size and shape.
Pay particular attention to how the tips of the lawn darts appear to be twisting, especially in the relative 1-2-5-6 and 10 o’clock positions. Remember that each half of the hearts is created by light reflecting off the pavilion main facet on the opposite side of the diamond.
When the length of the lower girdle facets is slightly different, then the length of the reflection will also be different, and thus the two halves which make up the heart, are comprised of light that is of different lengths, which creates the optical illusion that the tip of the heart is bending.
Are GIA Excellent cut diamonds hearts and arrows?
Here is another example of a GIA Excellent round brilliant cut diamond, as seen through a hearts and arrows scope. Arguably, I suppose that there are some people in the diamond business who would claim that this diamond exhibits a pattern of hearts and arrows.
However, you can clearly see that the heart in the six o’clock position is roughly half the size of the other lawn darts. Which indicates that there is a difference in the length of the lower girdle facets. Thus this round brilliant cut diamond is obviously not exhibiting a crisp and complete hearts and arrows pattern.
Which is not to say that some GIA Excellent cut diamonds will not exhibit hearts and arrows. It is important to understand that the GIA Excellent cut grading platform does not take hearts and arrows patterns into account. Neither the AGS Laboratory, nor the GIA Gem Trade Laboratory, take optical precision into account as part of their cut grade platforms.
Where to Buy Hearts & Arrows diamonds:
It goes without saying that we think the best place to buy hearts and arrows diamonds is Brian Gavin. There is a clear and distinct difference in the hearts pattern exhibited by every Brian Gavin Signature diamond.
Look at how consistent and precise the hearts pattern exhibited by this 1.750 carat, G-color, VVS-2 clarity, Black by Brian Gavin hearts and arrows round diamond appears to be. This diamond clearly exhibits a better pattern of hearts and arrows than we’ve seen in other round brilliant cut diamonds.
The secret is in the degree of optical precision that Brian Gavin Signature diamonds are cut to exhibit. It takes a higher degree of skill, and higher quality equipment (more expensive) to cut diamonds of this cut caliber.
However, the difference in light performance and sparkle factor is clearly apparent. This is the ASET Scope image for one of the GIA Excellent cut diamonds referenced above. Notice how the table facet region is very light pink, to the extent that it is practically transparent.
This is an indication of light leakage, and yet this GIA Excellent cut diamond has a 40.8 degree pavilion angle. Thus, you’d think it would be exhibiting a high degree of light return. It also has a 34.5 degree crown angle, so it should be exhibiting a virtual balance of brilliance and dispersion.
Now compare that with the intensity of color being reflected under the table facet of the 1.750 carat, G-color, VVS-2 clarity, Black by Brian Gavin hearts and arrows round brilliant cut diamond.
Both diamonds are photographed on a white background, so that isn’t why the GIA Excellent cut round is leaking more light. The difference is not the proportions either, because both diamonds have proportions in the middle of the spectrum for the ideal cut rating. The difference is in the degree of optical precision that each diamond was cut to exhibit.
And it doesn’t take a rocket scientist to tell you which diamond you should buy, because the reflector scope images provide all the scientific proof required to make a truly informed decision.