“Hi Todd, I bought my girlfriend an engagement ring through Blue Nile’s website a month ago today. It was shipped to me on June 6th which means I only have about 10 days left to return it. I’m not asking my girlfriend to marry me until our 2 year anniversary in August but by then it will be too late to return it so I wanted your opinion on the diamond I got and if i should keep it or exchange the diamond. I bought a diamond from Blue Nile before I read your article about what to buy when only looking at the paper online. ~ Thanks Matt.”
Oh man, this is just the sort of article which tends to get me in all sorts of trouble with my affiliates because the first thing they’re going to ask me when they read it (and they do read what I write about them) is going to be something like “What the heck Todd?!?! The diamond was SOLD and you killed it!” Well my friends, sometimes you have to take the good with the bad, and I warned you at the time we discussed my becoming an affiliate, that I’m not going to change my selection standards in order to help you sell more diamonds and sometimes that means that you’re going to lose some sales… The proportions of this diamond are so far off the mark, that I have to recommend that Matt return it as fast as possible for a refund. And since this diamond is not a “Blue Nile Signature Diamond” you can simply return it to whatever cutter produced this piece of drek (that’s Yiddish for excrement) and wash your hands of it.
But first we’re going to use it as an example of what not to buy so that Matt and my other readers can learn from it… First of all, this diamond is graded by the GIA Laboratory as weighing 0.75 carats, with Internally Flawless (IF) clarity, J-color with medium blue fluorescence, with a total depth of 62.8% (Holy Drek! Ha, Ha, Ha, Ha!) and a table diameter of 56% with a crown angle of 35.5° (too steep) which is offset by a 41.0° pavilion angle (just a little too steep) and a medium, faceted girdle and no culet. The overall cut rating of the diamond is GIA Excellent, which can be confusing because it leads people to think that the diamond has an “Excellent Cut” but I kind of think that the parameters for the GIA Excellent Cut rating are SO BROAD that you can drive a truck through it… hey, it’s just my personal opinion, nobody says that you have to abide by it, but I do have 25+ years of experience as a diamond buyer.
All right, so you already know what’s wrong with the proportions of this diamond… the total depth of the diamond is too deep at 62.8% because the crown angle and pavilion angle of the diamond are cut too steep. But why is this a problem? Well, for one thing, because a lot of the carat weight of the diamond is being wasted in depth, the outside diameter of the diamond is going to be a little smaller than it should be for a diamond of this carat weight… which simply means that the visible surface area of the diamond, is going to be smaller than it would be if the total depth of the diamond were cut within my preferred range of total depth which is between 59 – 61.8% (a full percent shallower than this diamond).
Maintaining an offset for the crown and pavilion angle measurements between 34.3 – 34.9 degrees for the crown angle, offset by a pavilion angle which is between 40.6 – 40.9 degrees is critically important, because these two angles are essentially the primary reflective surfaces, or “mirrors” of the diamond. If they are aligned properly, the diamond will be optimized for maximum light return, like a Tolkowsky Cut Diamond, but if they are not, light will leak out the sides of the diamond and be lost… and who wants to buy a diamond which was has not been optimized for maximum light return?
They say that Beauty is in the eye of the beholder, but when it comes to the proportions that a diamond is cut to, we’re talking about optimizing the diamond for brilliance, which is how bright our human eyes perceive a diamond to be. It is not only the amount of light return, but also the perception of intensity created by the internal and external reflections of white light, as judged by looking at the diamond in a face-up position.The inside of a diamond is a lot like a room full of mirrors, the angle at which the “mirrors” of a diamond reflect light, is largely dictated by the consistency of facet shape and alignment… get it right and everything looks perfect, get it wrong and everything gets distorted, just as the reflection of the woman pictured to the left is distorted in the top and bottom halves as the angle of incidence is changed by distorting the angle of the glass.[separator]
Actually the statement made in that heading is a little misleading, but as you can see from the screenshot which appears to the left, it’s a quote from the Blue Nile web site. This is kind of a matter of semantics, but it’s a pet peeve of mine, and it needs to be addressed… As a point of order, the GIA Laboratory does not “certify” diamonds, and it is clearly stated on the back of their diamond grading reports that they do not certify diamonds, rather they report the characteristics of the diamond at the time the diamond was graded. This statement should read “Blue Nile is the Largest Retailer of GIA Graded Diamonds” which I admit does not sound as cool, nor SEO friendly, but it’s technically accurate.[separator]
The entire concept of “GIA Certified Diamonds” is misleading because diamond grading is subjective and therefore the stated clarity grade and color grade is subject to change depending on the opinion of each diamond grader who evaluates the diamond… this of course is subject to their individual characteristics, such as vision, levels of caffeine consumption, emotional circumstances, etc., so gemological laboratories do not “certify diamonds” they merely grade them and issue a diamond grading report which states the assessment of the grader at that particular moment in time… and legally, they only have to be accurate within two clarity or color grades (!) which is why I do prefer the grading standards of Top Tier gemological laboratories like the GIA and AGS, because they tend to be more accurate and consistent in their grading practices than a lot of third and fourth tier gemological laboratories, which are often franchises owned and operated by independent gemologists.
All right, so I’m going to recommend that Matt return this particular diamond to Blue Nile, but he provided me with links to several other diamonds which he found on their web site after reading some of the tutorials on this web site, so we’re going to check those out and write a Blue Nile diamond review at the same time. Just keep in mind that these diamonds were selected by a consumer, so some will meet my selection criteria and others will not.
I’m really excited about this opportunity to write a comparison of Blue Nile and James Allen Diamonds, let’s take a look at these puppies and determine what the best options are!
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.
First up, we have this Round Brilliant Cut Diamond from Blue Nile which is graded by the GIA as weighing 0.72 carats, VVS-1 in clarity, J-color with medium blue fluorescence, and an overall cut rating of GIA Excellent. According to the GIA, it has a total depth of 62.2% (too deep) and a table diameter of 57% with a crown angle of 36° which is offset by a pavilion angle of 40.6° with a medium to slightly thick, faceted girdle and no culet.
Now if you remember the measurements for my preferred range of crown and pavilion angle from above, you’ll note that this diamond has a crown angle which is steeper than those measurements, and it’s costing us a little bit in terms of visible outside diameter… but it’s actually not all bad. In this particular instance, the 40.6° pavilion angle is going to produce a lot of light return and it’s a good offset for the steeper pavilion angle, because it’s all about adjusting the “mirrors” of the diamond so that they are optimized to reflect light off of each other for maximum output… so it works, but it’s not my preference, because the diamond is less likely to exhibit a virtual balance of brilliance and dispersion.
Dispersion, which is also known as “fire”, is the flashes of colored light that is created by the facets of a diamond. Technically these flashes of light are actually white, but our eyes break them up into colors like red, green and blue, if the optical symmetry of the diamond (which is discussed in this article on Tolkowsky Cut Diamonds) is cut precisely enough. Now it’s a well known gemological fact, that diamonds with steeper crown angles and small table measurements are more likely to exhibit a lot of fire, it’s also true that they are more prone to light leakage and thus the diamond is more likely to exhibit more dispersion than brilliance. I tend to prefer diamonds which exhibit more of a virtual balance of brilliance and dispersion, so I focus my efforts on finding diamonds with crown angle measurements between 34.3 – 34.9 degrees and pavilion angle measurements which are between 40.6 – 40.9 degrees. So this diamond is an excellent choice for somebody who prefers more fire in a diamond, than brilliance, but it wouldn’t be my first choice…
Next we have this Round Brilliant Cut Diamond from Blue Nile which is graded by the GIA as weighing 0.73 carats, SI-2 clarity, E-color with negligible fluorescence, and an overall cut grade of GIA Excellent. According to the GIA, this diamond has a total depth of 61.4% and a table diameter of 57% with a crown angle of 35° which is offset by a pavilion angle of 40.8° degrees with a medium to slightly thick, faceted girdle and no culet.
Okay now we’re getting closer, the only thing that I don’t like about the proportions of this diamond is that the crown angle is 0.01 of a degree off of my preferred range which is 34.3 – 34.9 degrees, and I might be able to live with that. However the primary inclusion is indicated as a feather, which is a minor fracture within the crystal structure of the diamond… Now if you read my article on diamond clarity characteristics, you’ll see that some feathers are perfectly fine and others might present a durability risk to the diamond.
The problem is that this diamond is accompanied by a GIA Diamond Dossier, which does not provide a plotting diagram. So there is no way of knowing the location or extent of the feather. For instance, the plotting diagram for this GIA graded diamond, enabled me to identify the location and extent of the feather and reject it because the position of the feather, as indicated by the red arrows which I added to the upper and lower portions of the plotting diagram, tells me that the feather runs from top to bottom through the girdle edge of the diamond and thus it “might present a durability risk” to the longevity of the diamond.[separator]
Imagine a dotted line running vertically down between the two halves of the diamond represented above, now fold the lower half of the diamond (right) down under the top half of the diamond (left) and you’ll see that the feathers align on both sides of the diamond… isn’t that tricky? But in this case, we’re unable to determine the location or extent of the feather which is the “grademaker” responsible for the SI-2 clarity grade of this diamond, and because it’s an SI-2 clarity diamond, the odds are that the feather is more extensive… so I’d pass on this Blue Nile diamond also.
This next option is more interesting to me… It’s a Round Brilliant Cut Diamond from Blue Nile which is graded by the GIA as weighing 0.73 carats, SI-2 clarity, G color with negligible fluorescence and an overall cut grade of GIA Excellent. According to the GIA, this diamond has a total depth of 61.5% and a table diameter of 55% with a crown angle of 34.5° which is offset by a pavilion angle of 40.8° and a thin to medium, faceted girdle and no culet. Now we’re talking, in terms of light return, this diamond has been cut to proportions which are optimized for maximum light return![separator]
The GIA Laboratory states that the clarity characteristics of this SI-2 clarity diamond are cloud, feather, crystal. Just like the option which we just discussed, this diamond is accompanied by a GIA Diamond Dossier, which does not provide a plotting diagram of the inclusions. However there is a difference, the clarity grade of the SI-2 clarity diamond discussed previously was only a feather, in this instance it’s cloud, feather, crystal… What’s the difference?
Here’s some critical insight for you… Gemological laboratories like the GIA and the AGSL, list inclusions on their diamond grading reports in order of their prominence within the diamond. So while the feather(s) within this diamond may or may not be located in a position, or extensive enough, to present any sort of durability risk, the odds are that they are less prominent than the feather(s) located in the other SI-2 clarity diamond that we discussed above. By the way, a “cloud” is merely a cluster of pinpoint size diamond crystals which are located in close proximity to one another, it sounds kind of like it might block light, but that is rarely the case. So this diamond remains of interest to me…
Now we’re getting somewhere… this Round Brilliant Ideal Cut Diamond from Blue Nile is graded by the GIA as weighing 0.79 carats, VS-2 clarity, J-color with negligible fluorescence and an overall cut grade of GIA Excellent. According to the GIA, this diamond has a total depth of 61.6% and a table diameter of 57% with a crown angle of 34.5 degrees which is offset by a pavilion angle of 40.8 degrees with a medium to slightly thick, faceted girdle and no culet.[separator]
This diamond is essentially cut to perfect proportions which are optimized for maximum light return! And according to the GIA, the clarity grade of this diamond is based upon crystal(s) which are most likely tiny diamonds which were trapped within the larger diamond crystal as it formed… it’s also common for crystals from other gemstones such as rubies or sapphires to become trapped within diamond crystal as it formed, either way, they’re cool by me.
All right so this next diamond is a Round Brilliant Ideal Cut Diamond from Blue Nile which is graded by the GIA as weighing 0.80 carats, SI-2 clarity, I-color with faint fluorescence, and an overall cut grade of GIA Excellent. According to the GIA, this diamond has a total depth of 61.6% with a table diameter of 56% and a crown angle of 34.5 degrees which is offset by a 40.8 degree pavilion angle with a thin to medium, faceted girdle and no culet… so it’s going to be rock solid in terms of light return!
However I never would have brought this diamond in for evaluation when I was the diamond buyer for Nice Ice, because the primary inclusions are indicated as “twinning wisps” which is a twisting of the crystal plane of the diamond, and it can present a durability risk. Here again, the decision to reject this diamond “off paper” has more to do with it being an SI-2 clarity diamond, which is accompanied by a GIA Diamond Dossier, than it is because of the inclusion type. Diamond clarity characteristics are likely to have a different impact upon a diamond in each of the different clarity grades, and the location and extent of the inclusion are always a factor… So I’m inclined to reject SI-2 clarity diamonds when the inclusions responsble for the clarity grade are twinning wisps, especially when I’m unable to get an idea of their location or extent, than I am to reject a higher clarity diamond with the same type of inclusions.
Now here’s another diamond which Matt picked that meets my selection criteria! It’s a Round Brilliant Ideal Cut Diamond from Blue Nile which is graded by the GIA as weighing 0.80 carats, VVS-2 clarity, J-color with negligible fluorescence and an overall cut grade of GIA Excellent. According to the GIA, this diamond has a total depth of 61.6% with a table diameter of 57% and has 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 proportions are spot-on! And as you can see from the plotting diagram featured to the left, the feather which is indicated by the red arrow that I added, is located well within the body of the diamond.[separator]
If you happen to be a super savvy connoisseur of diamond grading terminology, you might have noticed that I used the word “negligible” to describe the fluorescence levels of diamonds which the GIA graded as “none” and this is done intentionally… by gemological standards, the degrees of fluorescence which are described by the AGSL as “negligible” and by the GIA as “none” are identical, they represent a range of fluorescence which can be anywhere from absolutely none, up to not enough to be measured with any degree of accuracy ~ which is thus more accurately described as “negligible” which is why I prefer the terminology used by the AGSL.
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