Which Blue Nile Signature Diamond to choose?

“Which one would you pick out of these 2 diamonds? [Links Provided Below]. Our budget is up to $11,000 for the diamond and our main goal is to find a perfect symmetry cut diamond. Other factors can be flexible: color from H or above, Clarity vvs2-vs1. Carat: 1 ct or above. Our preference is Cut>Carat>Color>Clarity. Thank you so much for your help!” ~ C.W.

Note: Blue Nile changed the format of how deep links were created when they switched their affiliate network from GAN to CJ, and thus the original links to the following diamonds were broken and have been replaced with links directed to their diamond search engine, which is fine since these options have probably sold by now. Please use my free Diamond Concierge Service if you would like me to help you find the best options currently available, but the information that can be obtained by reading the article is still applicable even if the diamond details pages can not be accessed.

The first option which you referenced C.W., is this 1.15 carat, H-color, VVS-2 clarity, Signature Diamond from Blue Nile which is graded by the GIA Laboratory with an overall cut grade of GIA Excellent.  According to the GIA, the diamond measures 6.73 – 6.77 x 4.16 mm with a total depth of 61.6% and a table diameter of 56% with a crown angle of 35.0° which is offset by a pavilion angle of 40.6° with a medium, faceted girdle and no culet.  The primary inclusion is indicated as being a cloud of pinpoint size diamond crystals which is indicated towards the left edge of the table facet in the upper plotting diagram.

The next option is a Blue Nile Signature Diamond weighing 1.16 carats, which is VVS-2 in clarity and H-color with medium blue fluorescence this diamond also has an overall cut grade of GIA Excellent. According to the GIA, the diamond measures 6.76 – 6.80 x 4.17  mm with a total depth of 61.5% and a table diameter of 56% with a crown angle of 34.0° which is offset by a pavilion angle of 40.8° with a medium, faceted girdle and no culet. The primary inclusions within this diamond are indicated as being pinpoints, feathers, and needle shaped diamond crystals, none of which concern me.

The two diamonds are cut essentially equal, both have proportions which are within the guidelines for the zero ideal cut proportions rating as established by the American Gem Society Laboratory (AGSL), and they are pretty good options… however, neither of these diamonds meets my selection criteria for proportions which tends to be a bit tighter:

Total depth between 59 – 61.8%
Table diameter between 53 – 57.5% (possibly 58%)
Crown angle between 34.3 – 34.8 degrees
Pavilion angle between 40.6 – 40.9 degrees
Girdle: thin to medium, possibly slightly thick
Culet: GIA “none” or AGS “pointed” (same thing)

This set of proportions is essentially in the center realm of the parameters designated by the AGSL for the zero ideal cut proportions rating, and it is extremely close to the diamond design created by Marcel Tolkowsky, who is recognized as being the inventor of the modern round brilliant ideal cut diamond. Round brilliant cut diamonds cut within this precise set of proportions tend to exhibit a greater volume of light return than diamonds cut beyond this range.

Keeping in mind that your primary focus is Cut>Carat>Color>Clarity, I conducted a search on Blue Nile for diamonds within the range of characteristics which you specified, and my own selection criteria for proportions, and found this 1.14 carat, H-color, VS-1 clarity, Blue Nile Signature Diamond which is graded by the GIA with an overall cut grade of GIA Excellent.  This diamond measures 6.71 – 6.76 x 4.14 mm with a total depth of 61.4% and a table diameter of 55% with a crown angle of 34.5° which is offset by a pavilion angle of 40.8° with a medium, faceted girdle and no culet.  The primary inclusions consist of a few clouds of pinpoint size diamond crystals, a few feathers which are located well within the body of the diamond, and a few needle shaped diamond crystals, all of which look great to me.

Now the proportions of this diamond are dead center in the middle of my preferred range of proportions, which is pretty much dead center in the middle of the range of proportions established by the AGSL for their zero ideal cut proportions grade… and that means that this diamond should knock your socks off in terms of light return!  So between the three diamonds, I’d choose this one!

But your original inquiry asked which diamond I’d choose of the two options which you presented me with, and of those, I’d most likely choose the 1.16 carat, H-color, VVS-2 clarity, puppy because I prefer the combination of the 34.0 degree crown angle offset by the 40.8 degree pavilion angle, to the 35.0 degree crown angle and 40.6 degree offset of the 1.15 carat.

Perfect Symmetry in a Diamond:

You mentioned that your primary goal was to find a diamond with perfect symmetry, and I feel obliged to point out that there is no way to judge the optical symmetry of any of the diamonds featured on the Blue Nile web site, because they do not provide the gemological detail necessary to make that determination.  The only way to judge optical symmetry is to view the diamond while unmounted through an ASET Scope, an Ideal Scope and a Hearts & Arrows viewer.

I also feel obliged to mention that there is no such thing as “perfect” when it comes to diamonds, but there are definitely different levels of perfection.  For instance, I feel that this 1.135 carat, VS-1 clarity, H-color with medium blue fluorescence, diamond from the Brian Gavin Blue collection is superior in overall cut quality than any of the options from Blue Nile mentioned above, simply because I’m able to make that judgement call based upon what can be seen in the scope images which accompany that diamond.  First off, the diamond is graded by the AGS Laboratory on their platinum light performance grading platform which incorporates their Angular Spectrum Evaluation Tool (ASET) which is designed to grade the light return of the diamond, so we don’t have to guess about whether the diamond has been optimized for light return based upon the proportions, the lab had made that determination for us.

Second, Brian Gavin Diamonds (BGD) has provided us with an image of the diamond as seen through an Ideal Scope, which is designed to determine the extent and location of any light leakage… Looking at the image, I can see that the diamond is leaking a minimal amount of light, which is typical of a diamond of this overall cut quality, and that it is leaking light in all the right places.

The diamond measures 6.71 – 6.74 x 4.11 mm with a total depth of 61.0% and a table diameter of 57.1% with a crown angle of 34.9 degrees which is offset by a pavilion angle of 40.7 degrees with a thin to medium, faceted girdle and a pointed culet.  The inclusions consist of a few diamond crystals, needle shaped diamond crystals and clouds of pinpoint size diamond crystals, and this diamond sells for a little bit less than the 1.14 carat which I found from Blue Nile.

If you can stretch your budget just a bit, this 1.232 carat, H-color, VS-1 clarity, Brian Gavin Signature Hearts & Arrows Diamond is a five star contender! It also has an overall cut grade of AGS Ideal-0 on the platinum light performance grading platform and is cut to my preferred range of proportions, but it also exhibits a crisp and complete pattern of hearts and arrows as you’ll be able to see by the photographs provided on the diamond details page.

Now I’ll tell you a secret… both of these diamonds from Brian Gavin were produced by the same diamond cutters, on the same production line, so I know that they both have great optical symmetry! But I’m only able to verify the hearts and arrows pattern on one of them, because that’s how Brian Gavin separates their lines.  The odds are that I’d probably go with the 1.135 carat, because it fits within your price range and is going to be just as sparkly, but if you really want to buy the diamond from Blue Nile, then I’d definitely go with the 1.14 carat.

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

Leave a Comment: