Perception of diamond value. Deciding which ideal cut diamond to buy…

Hi! I’m looking for a diamond that has the most value. Preferably 1.40 – 1.99 carats, VS-2 – SI-1 clarity, F color. It does not have to be hearts & arrows, but it must be an ideal cut diamond. Would appreciate any recommendations that you can provide! Thanks so much! — Melissa

Thank you for your inquiry. The perception of “value” varies from person to person, I perceive it as being the diamond which is going to provide me with the highest volume of light return and best sparkle factor, thus I’m inclined to go for diamonds produced by cutters who I know cut diamonds to the highest levels of optical symmetry.

My two favorite producers of ideal cut diamonds are Brian Gavin and Crafted by Infinity which is distributed through High Performance Diamonds, I looked through their exclusive in-house inventories of super ideal cut round diamonds and found:

Examples of judging static contrast Brian Gavin Diamond Reviews, AGSL 104067973009This 1.563 carat, F-color, VS-2 clarity, Brian Gavin round ideal cut diamond with medium blue fluorescence, which will glow blue when exposed to black light as pictured on the diamond details page, but look perfectly normal the rest of the time… don’t know how you feel about that, but I happen to really like blue fluorescence in diamonds. This diamond has an overall cut grade of AGS Ideal-0 with proportions that are in the “sweet spot” which is widely recognized as producing the highest volume of light return, with a virtual balance of brilliance (white sparkle) and dispersion or “fire” (colored sparkle) while the 77% lower girdle halves will produce nice broad flashes of light!

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I also really like the look of this 1.535 carat, F-color, SI-1 clarity, round ideal cut diamond from Brian Gavin which exhibits medium blue fluorescence. The reality is that this diamond is going to face-up the same as the 1.563 carat, F-color, VS-2 clarity, diamond from Brian Gavin which is referenced above, the only real difference is going to be the visibility of the inclusions through a 10x diamond grading loupe.

Crafted by Infinity Diamond Review: AGSL 104069206002

Examples of judging contrast brilliance, Crafted by Infinity Diamond, AGSL 104069206002The next diamond I found is this 1.69 carat, F-color, VS-1 clarity, Crafted by Infinity round diamond, which is a bit up there in price just because it has a VS-1 clarity grade, but I felt that it is worthy of an honorable mention because it is also cut to the center of the range designated for the zero ideal cut proportions rating, and also has an overall cut grade of AGS Ideal-0 on the Platinum Light Performance grading platform which relies on Angular Spectrum Evaluation Technology (ASET) to measure diamonds for brightness, contrast, and other factors of visual performance. I wouldn’t hesitate to buy either of these diamonds for myself, they are exactly what I look for in a diamond.

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When shopping for and trying to compare the characteristics of ideal cut diamonds, it is important to realize that there are different levels of ideal, and different combinations of proportions, and different levels of optical symmetry, will produce diamonds which exhibit different volumes of light, different types of sparkle and even flashes of light which are different in size.

My personal preference leans towards ideal cut diamonds which are cut to the center spectrum of proportions, with a crown angle between 34.3 – 34.9 degrees, which is offset by a pavilion angle between 40.6 – 40.9 degrees because this will produce a high volume of light return with a virtual balance of brilliance and dispersion; with lower girdle halves in the range of 75 – 79%

James Allen Ideal Cut Diamond Reviews: GIA 1152669384

Examples of judging static contrast in diamonds, James Allen, GIA 1152669384I’d give this 1.72 carat, F-color, VS-2 clarity, round diamond from James Allen a grade of A- because the crown angle of 34.0 degrees is a bit shallower than I prefer, but the pavilion angle of 40.8 degrees is a great offset for it, thus the diamond should exhibit a high volume of light return with a bit more brilliance (white sparkle) than dispersion (colored sparkle) and the odds are that the 80% lower girdle halves are going to produce smaller flashes of pin-fire-like sparkle that are more like the sparkle cast off by a disco ball.

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While the average diamond buyer probably doesn’t give much thought as to the size and type of sparkle that the diamonds they are considering are likely to produce, the reality is that it is something which is a factor of visual performance because our eyes are less likely to be able to disperse smaller flashes of light into color, and thus we are more apt to perceive more brilliance than dispersion. If you think you might prefer diamonds which exhibit broader flashes of light, then I recommend sticking with options where the lower girdle halves measurement is between 75 – 79% but realize that this is just one piece of the puzzle and not the ultimate end all thing to look for.

For instance, you should also read the article on The Effect of Contrast Brilliance in Diamonds upon Sparkle Factor which I published on Tuesday, and then look at the arrows patterns for the three diamonds referenced above, I think you’ll develop an even better understanding of why I prefer the first two options. But realize that the diamond from James Allen is easily in the Top 1% of annual production (the other two are in the Top 0.001%) so it’s not like it’s not going to be amazing, there are just different levels of perfection within the realm of ideal cut diamonds, and with almost 30 years of diamond buying experience, I’ve become a bit of a snob when it comes to diamond cut quality and visual performance.

Ritani Round Ideal Diamond Reviews:

Another diamond which will exhibit pretty much the same volume of light return and size sparkle as the diamond referenced from James Allen above, is this 1.71 carat, F-color, VS-2 clarity, round diamond from Ritani, which has a 34.5 degree crown angle, that is offset by a pavilion angle of 40.6 degrees, so it should exhibit a high volume of light return with a virtual balance of brilliance and dispersion.

A slightly smaller option is this 1.50 carat, F-color, VS-2 clarity, round diamond from Ritani, which is likely to exhibit a bit more dispersion (colored sparkle) than brilliance (white sparkle) because of the 35.5 degree crown angle, but the volume of light return should be quite high because of the 40.8 degree pavilion angle. Understand that I consider this to be a viable option because different people have different preferences as to the balance of brilliance and dispersion exhibited by a diamond, while I definitely prefer more of a balance of the two factors, you might prefer more brilliance, or more dispersion. In this instance, the 75% lower girdle halves are more likely to produce larger, broad flashes of light instead of the disco ball effect provided by the other options from Ritani and James Allen.

At the other end of the spectrum is this 1.52 carat, F-color, SI-1 clarity, round diamond from Ritani, which is likely to exhibit a bit more brilliance than dispersion because of the 34.0 degree crown angle which is offset by a 40.8 degree crown angle. Here again it has lower girdle halves which are 80% so once again, it should sparkle like a disco ball.

Hopefully you’re beginning to see a pattern of how there are a wide variety of “ideal cut diamonds” produced with different combinations of crown and pavilion angle which will produce different volumes of light return, and types of sparkle, which create an ideal cut diamond that for every preference of how a diamond should look, and that there are many factors beyond the 4C’s of Diamond Grading that contribute to our perception of diamond value.

Blue Nile Ideal Cut Diamond Reviews:

The last step was to Search for Diamonds on Blue Nile, and as it turned out, they had several options available in this particular range of carat weight, color, and clarity, including this 1.44 carat, F-color, VS-2 clarity, round diamond from Blue Nile which has a crown angle of 35.5 degrees which is offset by a pavilion angle of 40.6 degrees, which as you know by now is likely to produce a high volume of light return with a little more dispersion / fire than brilliance.  And as with most of the options which we’ve discussed which aren’t from Brian Gavin and High Performance Diamonds, it has lower girdle halves which average 80% so it’s more likely to exhibit pin-fire-like sparkle.

Effect of very small culet round diamond reviews Blue Nile, GIA 5151539196Now there are a few things about this diamond that I’m not thrilled about, the first is the very small culet which is visible as a small black dot in the middle of the crown view clarity photograph that appears to the left, I’ve taken the liberty of highlighting it with a red arrow to make it easier for you to locate. Depending on your personal vision, you might be able to see the reflection of the very small culet within this diamond with just your eyes, I’ve always been able to and as a result I never purchased diamonds like this for inventory when I was the diamond buyer for Nice Ice. The second thing that I don’t like about this diamond is how the tips of some of the arrows are fading out,

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Unfortunately while I was hoping to be able to find you some options in the 1.40 – 1.49 carat range to consider, this 1.45 carat, F-color, VS-2 clarity, Signature round diamond from Blue Nile also has a very small culet which is also clearly visible in the clarity photograph provided in the crown view on the GCAL diamond grading report. Now it’s possible that you won’t be able to detect the very small culet with just your eyes, it’s all a matter of personal vision and most likely the experience of knowing what to look for… Here again, the diamond has a crown angle of 35.5 degrees which is more likely to produce a bit more dispersion / fire than brilliance, and it’s offset by a pavilion angle of 40.8 degrees with 80% lower girdle halves.

Interestingly enough, Blue Nile seems to have quite a few diamonds with very small to small culets in their inventory at the moment. For instance, both this 1.60 carat, F-color, VS-2 clarity, round diamond from Blue Nile, and this 1.60 carat, F-color, VS-2 clarity, round diamond from Blue Nile, and this 1.75 carat, F-color, VS-2 clarity, round from Blue Nile have culets which are small or very small.

Thankfully I did manage to find a few options for you to consider from Blue Nile which had no culets, for instance this 1.71 carat, F-color, VS-2 clarity, round diamond from Blue Nile might have potential; it has a crown angle of 35.0 degrees which is offset by a pavilion angle of 40.8 degrees with lower girdle halves which average 75% so it is likely to exhibit a high volume of light return, with a virtual balance of brilliance and dispersion, and broad flashes of light… but without a clarity photograph, we have know way of judging the degree of static contrast and thus we have no clue as to the degree of contrast brilliance that the diamond might exhibit.

Effect of 80 percent lower girdle halves measurements, Blue Nile round diamond reviews, GIA 1169002963Another diamond which looks interesting is this 1.73 carat, F-color, VS-2 clarity, round diamond from Blue Nile, which has also has a 35.0 degree crown angle which is offset by a pavilion angle of 40.8 degrees like the diamond referenced above, but this one has lower girdle halves which measure 80% and thus it is more likely to exhibit pin-fire-type sparkle than broad flashes of sparkle. Unlike the 1.71 carat referenced above, we do have a clarity image for this diamond that enables us to judge the degree of static contrast exhibited by this diamond. Now while the contrast of this diamond looks fairly good, do you notice how the pavilion main facets are different thicknesses?

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Are Blue Nile Signature Round Diamonds Hearts and Arrows Diamonds by Japanese or HRD grading standardsJust look at the thickness of the two arrows located at the top of the clarity photograph provided by Blue Nile above, and then look at the thickness of the arrow shafts as you move your eyes clockwise around the diamond… this is evidence of azamet shift, which indicates that the lower girdle facets located on the pavilion (lower half) of the diamond vary in length and width, and this is also affecting the hearts pattern which is visible in the lower clarity photograph, which prevents this Blue Nile Signature Round Diamond from actually being “Hearts and Arrows” as they claim all of them to be on the Blue Nile Signature Round Diamonds selection standards page.

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The paragraph featured on the graphic above reads: “The term Hearts and Arrows is used to describe the visual effect achieved in a round diamond with perfect symmetry and angles. The Hearts and Arrows effect is exhibited in all of our round Blue Nile Signature Collection diamonds. When viewed under special magnification, the perfectly aligned facets of the Blue Nile Signature diamonds reveal the Hearts and Arrows pattern. From the bottom, eight perfectly symmetrical hearts can be seen and, when viewed from the top, eight completely uniform arrows.”

Well I think it’s pretty clear that the facets of the Blue Nile Signature diamonds which we’ve looked at above, are far from perfectly aligned since the pavilion mains are different widths and the “hearts pattern” lacks any semblance of consistency. Sorry for the rant, but I find this type of thing to be completely irresponsible and more than a little misleading since the average consumer is not likely to be familiar with the grading standards for true Hearts and Arrows diamonds.

Todd Gray
Todd Gray is a professional diamond buyer with 30+ years of trade experience. He loves to teach people how to buy diamonds that exhibit incredible light performance! In addition to writing for Nice Ice, Todd "ghost writes" blogs and educational content for other diamond sites. When Todd isn't chained to a desk, or consulting for the trade, he enjoys Freediving! (that's like scuba diving, but without air tanks)
Todd Gray

@NiceIceDiamonds

Professional diamond buyer with 30+ years trade experience in the niche of super ideal cut diamonds. In my free time, I enjoy freediving & photography.
The incredible #story behind the Sirisha diamond necklace by @BrianGavin 71 #Diamonds cut to order #Amazinghttps://t.co/dHOo1T99xT - 2 years ago

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