The Secret Formula for Maximum Diamond Sparkle

“Hi, I read through your post on selecting the best Blue Nile Diamonds and picked a couple of diamonds out that I think meet the geometric recommendations that you laid out. Links below.  What I am looking for: Diamond over 1ct – 1.2ct Eye Clean Diamond will be set in a white gold setting (in the reading I’ve done it seems that J is probably ok for this esp. if the diamond has florescence). My Fiancee wants maximum sparkle. Thanks for your help!” – Max H.

The sentence which I locked in on from above is “My Fiancee wants maximum sparkle” because the primary focus of Nice Ice is to help people find diamonds which are optimized to deliver maximum light return and visual performance… the term “light return” refers to the volume of light being reflected back up through the top of the diamond; and “visual performance” refers to the sparkle factor in terms of brilliance, dispersion and scintillation.

Selecting diamonds which have proportions that fall within the “geometric recommendations” that I refer to throughout this web site is an excellent start, it will certainly result in diamonds which deliver maximum light return, but selecting diamonds for maximum visual performance is a little more difficult.

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.

Diamond Proportions = Light Return:

Blue Nile 1.06 carat, J-color, VS-1 clarity diamond, GIA #2146939924The 1.06 carat, J-color, VS-1 clarity, round brilliant cut diamond from Blue Nile which you referenced in your email, has zero ideal cut proportions, as indicated by the proportions diagram of the diamond, featured to the left, which I cropped from the GIA diamond grading report.  The specific range of proportions which I recommend is a total depth between 59 – 61.8% with a table diameter between 53 – 57.5% (possibly 58%) with a crown angle between 34.3 – 34.9 degrees offset by a pavilion angle between 40.6 – 40.9 degrees with a thin to medium, medium, or slightly thick, faceted girdle and a culet of either GIA “none” or AGS “pointed” (same thing).


This precise set of proportions is widely recognized as being the modern day equivalent of Tolkowky’s Diamond Design which defined the diamond proportions necessary to optimize round brilliant cut diamonds for maximum light return, brilliance, and dispersion. However, Tolkowky’s work never addressed the concept of scintillation, or how to optimize the optical symmetry of diamonds for maximum sparkle effect.

Optimized Optical Symmetry = Maximum Diamond Sparkle:

The first thing that you need to understand about “Optical Symmetry” in diamonds is that it is not taken into consideration when gemological laboratories, such as the AGS, GIA, EGL, or HRD, grade diamonds for Symmetry… so if you’re truly intent on maximizing diamond sparkle, you need to look beyond the overall cut grade of AGS Ideal-0 and GIA Excellent, to the realm of super ideal cut diamonds known as Hearts & Arrows.

Brian Gavin Signature Diamond, AGS #104060322039 Hearts & Arrows DiamondPictured to the left is the hearts pattern from this 1.173 carat, I-color, SI-1 clarity, Signature Diamond from Brian Gavin which is graded by the AGS Laboratory with an overall cut grade of AGS Ideal-0. The proportions are essentially equal to the Blue Nile diamond, it has a total depth of 61.6% and a table diameter of 57.1% with a crown angle of 34.5° and a pavilion angle of 40.8° with a thin to medium, faceted girdle and a pointed culet. So the light return is going to be relatively equal, however I’ll bet that this diamond will exhibit more sparkle and larger flashes of light, because it also exhibits a crisp and complete pattern of Hearts and Arrows.


Brian Gavin Hearts & Arrows Diamond, AGS #104060322039Crisp and complete patterns of Hearts & Arrows in round brilliant cut diamonds is a clear indication that each section of facets has been carefully crafted and aligned to maximize diamond sparkle and create contrast between the facet sections. The difference in contrast between the arrows pattern, which in this case is created by the reflection of a camera lens off of the pavilion main facets, and the rest of the facet structure of the diamond is clearly visible in this photograph of the 1.173 carat, Signature Diamond from Brian Gavin, which is referenced above. Under normal circumstances, this type of contrast will be created by the shadow of your head reflecting off of the pavilion main facets.


Diamond Contrast Checkerboard ExampleNow why is contrast in a diamond a critical factor of my selection process? Because contrast is what enables our eyes to see sparkle in a diamond and other gem stones… Take a look at this picture of a black and white checkerboard pattern. Are your eyes drawn outwards to the open sections of white which surround the image, or are they drawn inwards towards the checkerboard pattern? And which sections of the image appear more dramatic and appealing to you? The sections which are all white, or the section comprised of the checkerboard pattern? Most people will be drawn to the center region of the graphic, which is exhibiting the highest amount of contrast.


The same principle applies directly to diamonds and people tend to be most attracted to diamonds which exhibit the most contrast, but they usually don’t understand that contrast in diamonds is created by balancing a precise set of proportions with extremely precise optical symmetry.  Diamonds like this 1.173 carat, I-color, SI-1 clarity, Signature Diamond from Brian Gavin are measurably superior in light performance and visual performance, because they are designed to produce a higher number of virtual facets, which will result in larger flashes of light and more diamond sparkle.

Getting back to the Diamond from Blue Nile:

So the 1.06 carat, J-color, VS-1 clarity, round brilliant ideal cut diamond from Blue Nile is probably a truly beautiful diamond. If you hadn’t indicated that your fiance wanted maximum sparkle, I would have given it the Nice Ice Stamp of Approval and just said “buy it” because the proportions are dead center in the middle of the range which I designate as my selection criteria for proportions.  I am quite confident that this diamond exhibits maximum light return, because it has been cut to a set of proportions which is widely recognized as the optimum proportions for outstanding light return… so no worries there.

The inclusions are perfectly fine… just a couple of diamond crystals and a small feather. In terms of diamond cut quality, this diamond is easily within the Top 1% of annual production for round brilliant cut diamonds, it’s a Rock Star! But when people tell me that they’re looking for “maximum sparkle” or “superior visual performance” I start thinking “Super Star” and the reality is that Blue Nile simply doesn’t provide us with the imagery necessary to make that determination… Even the data provided in the GCAL report which accompanies their Signature Diamonds, does not contain sufficient data for me to make this determination, because it requires a picture of the diamond as seen through an ASET Scope, an Ideal Scope, and a Hearts & Arrows viewer.

Thus when people tell me that they want maximum diamond sparkle and visual performance, the production of only two diamond cutters comes to mind… Brian Gavin of Brian Gavin Diamonds, and Paul Slegers of Crafted by Infinity, because they both routinely produce diamonds of this cut quality, and they both provide the images necessary to verify the cut quality of their diamonds.  And just so you know, it’s not that GCAL isn’t capable of taking Hearts & Arrows images and adding them to their diamond grading reports, it’s an option which is available for a reasonable fee, so I have to assume that those images are not being provided for a reason…

Brian Gavin Blue Fluorescent Diamonds:

Blue Fluorescent Diamond from the Brian Gavin Blue collectionIt’s no secret that I’m a big fan of diamonds which exhibit blue fluorescence, because it acts like nature’s white wash and can help to boost the color of a diamond, just a bit, when the diamond is exposed to intense ultra violet light, and it just looks cool when the diamond is exposed to black light, like the photograph of this Brian Gavin Blue Fluorescent Diamond, pictured to the left, which weighs 1.164 carats, SI-1 clarity, I-color with very strong blue fluorescence. Now Brian does not provide H&A photographs of the diamonds featured in the BGD Blue collection, but I can tell you that they are produced right alongside his Signature Hearts & Arrows Diamonds.


Wait… that last part might be a Secret! Oh well, I’ve already typed it and I hate going back through stuff to edit it, especially when the text fits so nicely alongside that picture! Yea, sometimes decisions to reveal top secret trade secrets are made like that… Brian will just have to deal with it! Laughs!

So what I’m saying is that I’m confident, very confident, that the optical symmetry of the diamonds featured in the Brian Gavin Blue collection are comparable to the optical symmetry of the diamonds featured in the Brian Gavin Signature collection of Hearts & Arrows Diamonds, and thus the visual performance is also!

Hmmm, you didn’t tell me how much money you wanted to spend, but this 1.216 carat, I-color, SI-1 clarity, super ideal cut diamond from the Brian Gavin Blue collection looks spectacular! It has an overall cut grade of AGS Ideal-0 with center range proportions and inclusions which are truly minor… and all of the scope images look fantastic!

So does this 1.151 carat, J-color, SI-1 clarity, Crafted by Infinity Diamond which is being offered by High Performance Diamonds! The crown angle is actually 0.01° shallower than my preferred range, but the reality is that there is a little room in my calculations for the crown angle to go a little shallower than 34.3° but not much, and certainly not deeper than 35° and only under very specific circumstances… Do yourself a favor and don’t guess as to what those circumstances are, just ask me to help you find the diamond of your dreams.

Additional Options from Blue Nile:

Now I realize that it might seem like I’m trying to steer you away from the diamond which you found at Blue Nile, towards diamonds from either Brian Gavin or Crafted by Infinity, but that’s only because you indicated that your fiance wants maximum diamond sparkle.  But maybe the two of you are primarily interested in maximizing light return, and the improved diamond sparkle which is provided by the better “meet point symmetry” which is required to get the overall cut grade of GIA Excellent or AGS Ideal-0.

So I searched Blue Nile for round brilliant ideal cut diamonds which meet my selection criteria for diamond proportions, inclusions, and overall cut grade, and found these additional options for you to consider. It goes without saying that all of the links contained on this page are <==== Big Scary affiliate links ====> clicking on them contributes to running this web site and does not change your purchase price, so it’s a win/win. Your continued support of this web site and my efforts is appreciated!

Blue Nile Signature Diamond, weighing 1.152 carats, I-color, VS-2 clarity, with an overall cut grade of AGS Ideal-0 on the Platinum Light Performance grading platform which uses Angular Spectrum Evaluation Technology (ASET) to verify that the diamond is optimized to reflect the maximum amount of light back up to the observer. The total depth of the diamond is 61.3% and the table diameter is 56.9% with a crown angle of 34.9 degrees, which is offset by a pavilion angle of 40.8 degrees with a thin to medium, faceted girdle and a pointed culet. The inclusions are minimal and meet my selection criteria… It should be a gorgeous diamond and I have a lot more faith in the visual performance of diamonds graded on the AGSL Platinum Light Performance grading platform than the GIA Excellent grading platform because it’s very, very difficult to get an overall cut grade of AGS Ideal-0 using the ASET.  One thing that I want to point out, I noticed that the heading on this page references the carat weight of the diamond as 1.13 carats, but the lab report states 1.152 carats, make sure that you get the 1.152 carat diamond, because that’s the lab report that I’ve based this recommendation upon, and there is a discrepancy between the carat weight stated on the GCAL report as well… I’ve already sent an email to my contact at Blue Nile to ask “what’s up?”

This Blue Nile Round Brilliant Ideal Cut Diamond weighing 1.16 carats, I-color, VS-2 clarity, is cut to center range zero ideal cut proportions, and has an overall cut grade of GIA Excellent.  It is comparable to the 1.06 carat puppy that you mentioned in your email, it has a total depth of 61.8% with a table diameter of 57% and 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.  The primary inclusions are just a couple of diamond crystals, small feathers, and needle shaped diamond crystals.  The comment “additional clouds and pinpoints not shown” simply means that additional groups of pinpoints size diamond crystals, called clouds, and a few pinpoint size diamond crystals, are not indicated on the plotting diagram… this is usually because they are so minute, that they are insignificant and not a primary influence upon the clarity grade of the diamond, but are mentioned because they are technically present.

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


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 #Amazing - 1 year ago

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