How does Very Good Symmetry vs Excellent effect Diamond Sparkle

Does this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani have more light shining on it in the video? Or is it positioned just right with the light or something? Because I haven’t seen this much sparkle on any of the other Ritani diamond videos that I’ve looked at. I’m really hoping that you can tell me that it’s a light-thing, because it is a little more money than we want to spend. This diamond only has GIA very good symmetry, but it is dazzling. I’ve noticed that Ritani doesn’t provide clarity images and videos for all of their diamonds. Do they only put the best looking ones up? In other words, are the diamonds without videos and pictures inferior in any way? — A. Williams

Very Good Symmetry vs Excellent for a round diamond:

Effect of very good symmetry on diamond sparkle, Ritani diamond reviews, GIA 2155728560The diamond grading report issued by the GIA for this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani indicates that the diamond has Very Good symmetry, and people often want to know whether very good symmetry is good enough… The short answer is “probably not” because while this diamond from Ritani might look great in the video where it is being pumped full of light, the static clarity photograph provides insight into how the very good symmetry is going to affect the visual performance of the diamond in real life. The thing that tends to mislead people with diamonds such as this, is that “by the numbers” the proportions of this diamond appear to be within tolerance of my preferred range as stated in the article 15 Seconds to Diamond Buying Success, the crown angle is 34.5° and the pavilion angle of 41° is only one tenth of a degree beyond those parameters.

While the proportions of this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani might appear to be acceptable at first glance, you need to look past the crown and pavilion angle measurements and take the crown height and pavilion height measurements into account to fully understand the impact that the proportions of this diamond are likely to have upon the volume of light return and sparkle factor…

Effect very good symmetry on contrast of arrows pattern, Ritani diamond review, GIA 2155728560The crown angle of the diamond is 34.5 degrees and the crown height is 15% which are great. However, the pavilion angle is 41.0 degrees and the average pavilion depth is 43.5% which happens to be pretty steep, and this is most likely why the pavilion main facets are exhibiting signs that light is not reflecting off of them properly… Just look at how the tips of the arrows are fading out to the extent where they are barely visible, as indicated by the green arrows in the photograph of the diamond that appears to the left. Now look carefully at the space located between the two red arrows, can you see the difference in how the shadow created by the camera lens is reflecting off of the pavilion main?

Specifically do you see how part of the pavilion main facet appears to be dark, while another portion of the arrow shaft is light grey in color? And then do you see how the shafts on all of the pavilion main facets are different widths? And different shapes? This is most likely why the diamond only received a symmetry grade of very good from the GIA Laboratory. This type of variation in the size and shape of the pavilion main and lower girdle facets of the diamond will have a direct effect on the visual performance of this diamond.

And the average pavilion depth of 43.5% is contributing to the problem by affecting how light reflects off of the pavilion facets of the diamond, and these are the facets which are supposed to catch the light which enters a diamond and direct it back up towards the person viewing the diamond… Keep in mind that this measurement is the average of eight individual measurements, thus there are sections of the pavilion which are actually deeper than 43.5%

Ways that Diamond Cutters increase profits on diamonds:

According to the GIA, this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani measures 7.32 – 7.38 x 4.54 millimeters. If we run those measurements through the formula for estimating the carat weight of a round brilliant cut diamond, which I explain how to use in the article Brian Gavin Signature vs Crafted by Infinity vs Whiteflash A Cut Above diamonds, you’ll see that the estimated weight of this diamond by formula is 1.49 carats.

While the difference of one point of carat weight might not seem like a big deal to you, from my perspective whoever cut this diamond cheated the stone by leaving too much weight in the lower half of the diamond, and by leaving too  much carat weight in the girdle edge of the diamond, which enabled him to push the carat weight of the diamond over the 1.50 carat mark and take advantage of the price increase that occurs between the 1.49 – 1.50 carat marks, which is a difference of two thousand dollars per carat in this instance. In other words, this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani would probably cost about three thousand less if it had ended up weighing 1.49 carats because the cutter cut the pavilion depth to the slightly shallower range that I prefer.

Obviously it makes sense for the diamond cutter to “cheat the stone” by leaving a little extra carat weight in the pavilion and girdle edge sections, doing so enabled him to pick up another three grand off the same piece of diamond rough. However from the perspective of a seasoned diamond buyer like myself, the average difference of half a percent in the pavilion depth of the diamond has created signs that indicate the likelihood for decreased visual performance.

Ritani Round Diamond Review: GIA 21557431316

Ritani Round Diamond review, GIA 21557431316, SKU D-M7WNF7If you’re going to stretch your budget to this price range, then I’d be more inclined to select this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani which has an overall cut grade of GIA Excellent, but more importantly it has a better balance between the pavilion angle of 40.8 degrees and the pavilion depth of 43% and therefore it should exhibit better visual performance. The crown height of 14.5% is a little shallower than I prefer, but this will primarily affect the balance of brilliance and dispersion, not the volume of light return.

Once again if you run the measurements of this diamond through the formula for estimating the carat weight of a round brilliant cut diamond, you’ll discover that the estimated carat weight is 1.48 carats, therefore we know that the carat weight of this diamond was pushed over the 1.50 carat mark in some manner… probably in the form of cutting the crown angle to be just a hint steeper than it should be for a crown height of 14.5% and by leaving a little extra weight within the medium to slightly thick girdle, and perhaps by how the pavilion and crown facets were brought into the girdle section of the diamond. However there is no way for us to tell for sure without a manufacturer’s computerized proportions analysis and by looking at the diamond through the reflector scopes which are designed to enable us to judge the optical symmetry, and Ritani does not provide this on their diamond details pages.

With that in mind, I still feel that this 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani is a better option than the one with very good symmetry that you asked me about, but not by much and that’s why I personally would select this round brilliant cut diamond from Ritani:

Ritani Round Diamond Review: GIA 2177041082

Ritani round diamond review, GIA 2177041082, SKU d-190sysThis 1.36 carat, H-color, VS-2 clarity, round diamond from Ritani has an overall cut grade of GIA Excellent and measures 7.11 – 7.15 x 4.39 mm, and if you run those numbers through the for estimating the carat weight of a round brilliant cut diamond, you’ll find that the estimated carat weight of the diamond is also 1.36 carats, which means that you’re getting a diamond that faces up the diameter of a diamond that is the carat weight which you are paying for. The crown height is 15% and the pavilion depth is 43% which is absolutely perfect.

The crown angle is just a little shallower than I prefer at 34.0 degrees, but I’m good with that since the crown height is a good balance for the pavilion depth, and the pavilion angle of 40.8 degrees is spot-on… so I’m confident that this diamond has the potential to exhibit a high volume of light return with a virtual balance of brilliance and dispersion.

Now if you look at the diamond details  page for this 1.36 carat, H-color, VS-2 clarity, round diamond from Ritani you’ll notice that the there is a stock image of a diamond pictured, and there is not yet a video of the diamond… this most likely just means that Ritani has not got around to photographing the diamond yet, just click on the button to Request Actual Diamond Imagery that appears beneath the stock photo of a round brilliant cut diamond.

If experience is any kind of an indicator, the odds are that the difference we’re going to see between the Very Good Symmetry vs Excellent Symmetry grades of the 1.50 carat, I-color, VVS-2 clarity, round diamond from Ritani which you inquired about, and this 1.36 carat, H-color, VS-2 clarity, round diamond from Ritani, will be a more clearly defined arrows pattern which exhibits a higher degree of contrast… which will result in a higher degree of static contrast, which will enable the diamond to appear as if it is sparkling even when it is being viewed in lighting environments where there is less intense light than what is being used to illuminate the diamonds in the videos provided by Ritani… and that’s a real-world difference that is worth paying slightly more for.

About the Author 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)

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