Blue Nile Reviews the Best 1.50 Carat Round Diamond $10K

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March 3

“Hello Todd, My boyfriend and I have begun the ‘search for a diamond’ process, and I can’t help but feel overwhelmed. Mostly because I am not a diamond expert… and I do not want to become one. I merely want something beautiful and sparkly on my finger without finding out later that I got screwed.”

“I would like to get a diamond (rock only) for under $10k in the 1.5 carat range. I do not necessarily mind a few small inclusions, I just want it to really sparkle. I see tons of diamonds on Blue Nile that are priced loads less than diamonds of a similar size, cut, and clarity that I see in stores.”

“So I’m thinking that the internet is the way to go. When I look at GIA reports that show inclusions, I’m unsure which will be the best / look the most sparkly. I read about feathers, clouds, etc., on your site and I just don’t know enough. Can you make some suggestions? Thanks! – Jen”

Thank you for your inquiry Jen, I think that many people who are shopping for a diamond online share your concern about not wanting to find out later that they got screwed… and it’s easy to get ripped off when buying a diamond if you really don’t know what you’re doing! Let’s see whether I can help you avoid some of the pitfalls involved with buying a diamond online.

What makes diamonds sparkle?

In my experience the majority of diamond buyers want a diamond which really sparkles, however very few of them understand the factors of diamond cut quality which dictate how bright and sparkly a diamond will be… there are two primary factors of diamond cut quality which affect the volume of light return and type of sparkle exhibited by a diamond:

  • Diamond Proportions
  • Optical Precision

The proportions of the diamond are based upon the measurements for table diameter, crown angle, pavilion angle, girdle thickness and culet size. Each section of the diamond must be precisely aligned with the next section for light to travel properly through the diamond and be reflected back up towards the person viewing the diamond. If the sections of the diamond are cut too deep, or too shallow, then the volume of light reflected by the diamond decreases dramatically.

The American Gem Society Laboratory created a grading system based which takes the proportions of a diamond into account, diamonds with proportions which are most likely to exhibit the highest volume of light return are graded as AGS Ideal-0 or “zero ideal cut” while diamonds which exhibit lesser degree of light return are graded on a numerical scale which runs from AGS-1 Excellent out to AGS-10 Poor.

With the understanding that every range of proportions is exactly that… a range, which therefore has a middle spectrum which is the “sweet spot” and outer edges which are closer to being AGS-1 Excellent or lower in proportions, my preferred range of proportions and selection criteria for round brilliant cut diamonds is as follows:

  • Total depth between 59 – 61.8%
  • Table diameter between 53 – 58%
  • Crown angle between 34.3 – 34.9 degrees
  • Pavilion angle between 40.6 – 40.9 degrees
  • Girdle thickness between 0.7% thin to slightly thick
  • Culet of GIA “none” or AGS “pointed” (same thing)

In my experience, round brilliant cut diamonds cut within this range of proportions will exhibit an extremely high volume of light return and be extremely bright as a result.

Brian Gavin Reviews Hearts and Arrows Diamonds, AGSL 104062572002Superior levels of Diamond Sparkle is the result of combining ideal proportions with exceptional optical precision, which is the consistency of facet shape, size, and alignment. The pattern of hearts and arrows pictured to the left, which is visible within this 1.346 carat, K-color, VS-1 clarity, Brian Gavin Signature round diamond, is the direct result of a combination of super ideal proportions with an exceptional level of optical precision. If the indexing of the facets was off even slightly, the pattern of hearts and arrows would be irregular in size and shape, and exhibit signs of Azamet shift such as twisting in the tips of the hearts, or swirling of the arrowheads, or both…


The reason why I’m using a diamond from the Brian Gavin Signature collection as an example of AGS Ideal-0 proportions, combined with exceptional optical precision, is because the odds are that I won’t be able to find a diamond like this within the inventory of Blue Nile; and even if I could find a diamond similar to this within their inventory, they don’t provide the reflector scopes necessary to judge optical precision on their diamond details pages ~ and this is an issue for detail oriented diamond buyers like myself because it’s practically impossible to ensure that the diamonds which I recommend from Blue Nile are going to exhibit the highest levels of light return, brightness, and sparkle, since the information necessary to make that judgement call are not available.

With this understanding in mind, I searched for diamonds on Blue Nile within the range of 1.40 – 1.60 carats, and SI-2 up to Internally Flawless in clarity, with a wide open range for diamond color, and a price cap of $10,500 and was presented with 46 options within the limits of diamonds of what Blue Nile consider to be “ideal diamonds” and then I flipped through the lab reports to find the options which were within tolerance of my preferred range of proportions, and which contain inclusions which I find to be acceptable… let’s review those options:

Blue Nile Reviews: GIA 2151295608

Blue Nile Diamond Reviews, GIA 2151295608This 1.40 carat, I-color, VS-2 clarity round brilliant cut diamond from Blue Nile exhibits medium blue fluorescence and is graded by the GIA with an overall cut grade of GIA Excellent and has a crown angle of 35.0 degrees which is offset by a pavilion angle of 40.6 degrees, which is likely to result in a high volume of light return while the crown angle delivers a virtual balance of brilliance and dispersion.

The crown angle is only one-tenth of a degree beyond my preferred range of 34.3 – 34.9 degrees and that is a difference that is acceptable. The primary inclusions are indicated as being crystal, cloud, needle, feather, all of which appear to be minimal and of no consequence. This diamond has the potential to be a great performer, it’s just too bad that Blue Nile doesn’t provide the reflector scope images that we need to judge the contrast and level of optical precision.

Part of the challenge is that this diamond is part of the extensive virtual inventory of GIA graded diamonds which Blue Nile has arranged to have the exclusive right to market online, if it were part of the Blue Nile Signature Diamond collection, it would at least be accompanied by the supplementary GCAL diamond grading report which provides us with clarity images of the diamond and some indication as to the brightness… it’s still an incomplete representation of the diamond in my opinion, but it’s better than nothing.

Since I want more information than Blue Nile is able or willing to provide, the reality is that if I were interested in this diamond, I would ask Brian Gavin to see whether they can access the diamond off of the multiple listing service (MLS) from where Blue Nile is simply republishing the listing from, and get a more in-depth and thorough evaluation of the diamond.

If this concept seems kind of underhanded, rest assured that I’ve requested that Blue Nile provide this type of detailed information for my clients on multiple occasions, and discovered the process to be problematic and a total and complete waste of time… even I have several open customer service requests that remain unresolved with Blue Nile, despite asking higher management to intervene.

And since Blue Nile has secured exclusive rights to list a large majority of the GIA graded diamonds which are available on the MLS, searching for diamonds on Blue Nile remains one of the only ways for you to get a reasonable idea of what is available, but that doesn’t mean that you have to purchase from them.

Blue Nile Diamond Reviews: GIA 2125161277

Blue Nile round diamond reviews, GIA 2125161277This 1.40 carat, J-color, VS-1 clarity, round diamond from Blue Nile is also part of the virtual inventory which they are simply republishing off of the MLS used by the diamond industry to market diamonds globally, thus it is most likely available from any dealer which you choose to work with and most likely for the same exact price.

This diamond has a 35.0 degree crown angle which is offset by a pavilion angle of 40.8 degrees, thus we know that it is likely to exhibit a high volume of light return with a virtual balance of brilliance and dispersion. But once again, we have no way of judging the optical precision of the diamond, or the degree of contrast. Nor the potential sparkle factor which results from higher levels of diamond cut quality. The primary inclusions are listed as being clouds and needles, all of which are merely different types of diamond crystals that were trapped within the larger diamond crystal as it formed and thus are of no concern.


Blue Nile Round Diamond Reviews: GIA 6165287647

Blue Nile round diamond reviews, GIA 6165287647Another diamond which I feel has great potential is this 1.41 carat, I-color, VVS-2 clarity, round diamond from Blue Nile which has an overall cut grade of GIA Excellent and a crown angle of 35.0 degrees which is offset by a pavilion angle of 40.6 degrees. The primary inclusions are listed as being pinpoints, which aren’t going to be very apparent in a VVS-2 clarity diamond. While inclusions have very little to do with the volume of light return and sparkle factor of a diamond, some people definitely prefer diamonds which are pristine in appearance both with and without the 10x magnification which is the industry standard for diamond clarity grading. Of course I realize that you are hoping for a slightly larger diamond, however this diamond might appeal to somebody else who reads this Blue Nile Diamond Review who likes higher clarity stones and might not be as concerned about carat weight.


Blue Nile GIA Certified Diamond Review: GIA 2151880210

Blue Nile GIA Certified Diamond Reviews, GIA 2151880210GIA Certified Diamonds” laughs… Their wording not mine, I just couldn’t help it! All right, we’re finally getting over the 1.50 carat mark with this 1.54 carat, J-color, VS-2 clarity, round diamond from Blue Nile which has an overall cut grade of GIA Excellent ~ which some people in the industry refer to as “GIA 3X diamonds” because the cut grade is based on the cumulation of individual grades of Excellent for (1) Polish; (2) Symmetry; and (3) Proportions; for an overall cut grade that is commonly referred to as GIA 3X or GIA Triple Excellent.


It should be noted that the proportions criteria relied on by the GIA is significantly broader in scope than that defined by the AGSL for their zero ideal cut rating, and both are well beyond the scope of my preferred range of proportions which are intended solely to provide my clients with the best options in terms of light return and sparkle, not appease the diamond cutters who are continually pushing the gemological laboratories to broaden the range of their proportions grades, so that they can cut slop which enables them to yield more carat weight.

This diamond has a crown angle of 34.5 degrees which is smack dab in the middle of my preferred range of crown angle, however the pavilion angle of 41.0 degrees exceeds my preferred range by one tenth of a degree, and that is beginning to push my comfort zone for the pavilion angle because it is the primary surface that dictates the volume of light return, whereas the crown angle has more of an impact upon the type of sparkle… so while I’m apt to let a pavilion angle of 41.0 degrees slide when the crown angle is so perfect, I would have rejected this diamond flat out if the lab report indicated that the pavilion angle was any deeper.

Blue Nile GIA 3X Diamond Reviews: GIA 2151857807

Blue Nile GIA 3X Diamond Reviews, GIA 2151857807I think that this 1.57 carat, J-color, VS-2 clarity, GIA 3X round from Blue Nile is another viable option because the 35.0 degree crown angle is a good offset for the 40.6 degree pavilion angle, the diamond should exhibit a high volume of light return with a virtual balance of brilliance and dispersion.

The primary inclusions are indicated as diamond crystals and needle-shaped diamond crystals, so here again there is nothing to worry about in terms of the inclusions, and the VS-2 clarity grade virtually ensures that the diamond will be eye-clean.

Are SI-2 clarity diamonds from Blue Nile eye clean?

Are Blue Nile SI-2 clarity diamonds eye clean, GIA 2155875738I receive a lot of email from people regarding stones like this 1.65 carat, I-color, SI-2 clarity, round diamond from Blue Nile that ask whether it’s possible for an SI-2 clarity diamond to be eye-clean by looking at the inclusions indicated on the plotting diagram or a clarity photograph.

The reality is that the only way to determine whether an SI-2 clarity diamond from Blue Nile is “eye clean” is to have it evaluated by an experienced diamond grader who can make the judgment call by looking at the actual diamond.

There is absolutely no way that anybody can judge whether an SI-2 or SI-1 clarity diamond is going to be eye clean, or has the potential to be eye clean, by looking at a two-dimensional pen and ink portrayal of the diamond as represented by the plotting diagram provided on a diamond grading report, nor a clarity photograph. This however does not seem to prevent people who market virtual diamonds online without ever seeing them, from making statements like “it’s most likely eye clean” and the reality is that most SI-2 clarity diamonds are not eye clean by my standards.

Thus while I’m confident that this diamond is going to exhibit a high volume of light return because of the 40.6 degree pavilion angle, and that it will exhibit a virtual balance of brilliance and dispersion because it is offset by a 34.5 degree crown angle, I’m not so certain as to the visibility of the inclusions which may or may not be readily and immediately visible without magnification.

Especially since the primary inclusions within this diamond are indicated as being twinning wisps, which is twisting of the crystal planes of the diamond, which often contain diamond crystals of various sizes, shapes, and colors.hus I recommend having the diamond evaluated by somebody like Brian Gavin who can look at the diamond in-person and determine the visibility of the inclusions from a distance of 9 – 12 inches which is the industry standard for determining whether a diamond is eye-clean.

This completes my review of the diamonds which are currently being advertised by Blue Nile within the range of carat weight and price that you are working within, combined with my own preferred selection criteria for proportions. While all of these diamonds have the potential to be amazing, the reality is that we need the insight which would be provided by the various reflector scope images to be certain, and Blue Nile does not provide this information, not even for their Blue Nile Signature Diamonds and thus I’m hesitant to recommend any of them without the additional insight that can be provided by working with another dealer like Brian Gavin Diamonds, who are well known for providing diamond details pages which are extremely in-depth.

In an effort to provide you with some options that definitely meet my selection criteria, I expanded the diamond search to include options from these two preferred vendors of ideal cut diamonds:

Brian Gavin Signature Diamond Review: AGS 104069928013

Brian Gavin Signature Round Diamond Reviews, AGSL 104069928013This 1.452 carat, J-color, VS-2 clarity, Brian Gavin Signature round diamond is in the process of clearing the AGS Laboratory from being graded and thus we only have the details provided by the Diamond Quality Document issued by the AGSL for this diamond, but we already have more information to go on because the Light Performance grading platform provides us with an image of the diamond as seen using Angular Spectrum Evaluation Technology (ASET) which evaluates the brightness of the diamond and demonstrates where it is gathering and reflecting light from within the room! So we don’t have to assume that this diamond is reflecting a lot of light because of the 40.7 degree crown angle, nor whether the 34.2 degree crown angle is a good offset for the pavilion angle, nor whether the diamond is exhibiting good contrast, or whether it is going to be nice and bright…


What do the different colors of an ASET mean? Brian Gavin Diamond Reviews, AGSL 104069928013Because one look at the results of the ASET scan provided on the DQD, which is pictured to the left, and we know that all of these things are true. But what do all the colors of an ASET scan mean? The color red is used to represent the brightest light which makes the diamond brilliant, it is light which strikes the diamond from 45° to perpendicular with the table facet. The color green represents the 2nd brightest light which strikes the diamond from 45° out to the horizon. Since both red and green represent light which enters the diamond from 45° it is common for the two colors to overlap, especially within the table region where you will sometimes see a checkerboard like pattern of red and green.


The color blue indicates areas where light could have entered the diamond, but which is being blocked by the observers head, which creates contrast and that is important because it enables us to perceive depth within the facet structure of the diamond. One of the things which I love about the round brilliant ideal cut diamonds offered by Brian Gavin is that he produces high contrast diamonds, which makes them appear as if they are sparkling even when they are not, for instance when they are viewed in an office environment where fluorescent lighting is used and there is an insufficient amount of ultra violet light to create sparkle in the diamond… they still look they are sparkling to me because of the contrast that appears between the different facet sections.

Brian Gavin Signature Round Review: AGSL 104069928009

Another option which looks good to me is this 1.478 carat, J-color, SI-2 clarity, Brian Gavin Signature round diamond which is also just in the process of being added to their inventory… the diamond has proportions which are right in the middle of the spectrum designated for the zero ideal cut rating from the AGSL, and has an overall cut grade of AGS Ideal-0 as determined on their proprietary Light Performance grading platform.

The diamond quality document for the diamond is currently available from the diamond details page, and over the next few days Brian Gavin will add a high resolution video of the diamond, a clarity photograph, a picture showing how the diamond looks through an ASET Scope, an Ideal Scope, and a Hearts and Arrows viewer. In addition, I expect that Brian Gavin will provide an indication as to whether the diamond is eye clean or not, so we don’t have to guess as to whether the inclusions within the diamond are going to be readily and immediately visible without magnification.

About the Author

Dive deep into the glittering world of diamonds with Todd Gray, the CEO of Gray Matter Development, LLC. Todd has 35+ years of experience as a diamond buyer and trade consultant. He ghostwrites content for several online vendors and is an avid Freediver, currently exploring the Cenotes of Yucatan, Mexico. Dive into brilliance with Todd Gray!