How Does Diamond Shape Affect Price

The market price of a diamond is affected by many factors, such as the Carat weight, Clarity, Color, and Cut quality, which comprise the foundation of diamond grading commonly known as The 4C’s of diamond grading. However the shape of a diamond is also a contributing factor to the sale price. The diamond rough used to produce different shape diamonds commands different prices in the market, due to supply and demand, but also the ability for certain shapes of diamond rough to yield diamonds of larger carat weight with less loss of rough. The diamond rough used to produce round brilliant cut diamonds happens to be the most expensive and most sought after form of diamond rough.

The following graphic produced by Blue Nile indicates that you can save up to 25% off the price of a round brilliant cut diamond, by selecting a fancy shape diamond of similar size and quality. Note that the prices shown represent the current lowest price for diamonds from 1.00 to 1.05 carats with a minimum of Very Good cut, G color, VS2 clarity, Very Good symmetry, Very Good polish and Faint fluorescence:

How does diamond shape affect price. Search Blue Nile diamonds.

It is important to recognize that the fluctuation in prices between the different diamond shapes represented on this graphic might also be affected by differences in the degree of optical precision that each diamond has been cut to. Understanding diamond prices is not as simple as merely comparing the diamond shape, carat weight, color, clarity, intensity of fluorescence, polish and symmetry into account.

How do diamond proportions and cut quality affect price:

The proportions and the degree of precision that the actual facet structure of the diamond exhibits when viewed through an ASET Scope, Ideal Scope, and a Hearts & Arrows Scope is also a factor that affects diamond prices. We refer to the consistency of facet shape, facet size, and the indexing of the facets as they have been polished on to the surface of a diamond as optical precision. Some people refer to this as optical symmetry, however I find that term to be confusing since it is not related to the symmetry grade reflected on diamond grading reports, which only refers to “meet point symmetry” which is how precisely the tips of the facets meet up with one another.

The proportions that a diamond has been cut to, and the degree of optical precision can affect the market price of a diamond by as much as sixty percent! And the extra expense is worth every penny, because the proportions of the diamond will dictate the volume of light return that is exhibited by the diamond, and the degree of optical precision will affect the size and intensity of the sparkle, as well as how much light is or is not leaking out of the diamond.

The thing to understand is that it is not as easy to predict the visual performance of fancy shape diamonds “by the numbers” as can be done with round brilliant ideal cut diamonds, because the facet structure and overall shape of the are not completely symmetrical. The outline or shape of fancy shape diamonds can vary dramatically from one stone to the next, whereas the shape of a round brilliant cut diamond is always a tightly shaped circle.

For example, everybody tends to think of princess cut diamonds as being square in shape, which would mean that the length and width of the diamond would be relatively equal. However some princess cut diamonds are more rectangular in shape. The way to determine whether a fancy shape diamond such as a princess cut diamond is going to look square or rectangular is to determine the Length to Width ratio.

Got a calculator? Whip it out! Punch this in:

How to calculate length to width ratio of princess cut diamonds, Brian Gavin AGSL 104075727002 ASETTo calculate the length to width ratio of a diamond, simply divide the length of the diamond by the width. Let’s use this 1.045 carat, G-color, VS-1 clarity, Brian Gavin Signature Princess cut diamond as an example. According to the Diamond Quality Document (DQD) issued by the American Gem Society Laboratory (AGSL) for this diamond, it measures 5.46 x 5.41 x 4.15 millimeters. So we divide 5.46 by 5.41 and we get 1.009 which we’ll round off to 1.01 and express the length to width in terms of 1.01:1.00 which lets us know that the diamond is relatively square. A perfect square would have a length to width ratio of 1.00:1.00 and as you can see from the ASET image pictured to the left, this BGD Signature Princess cut diamond looks pretty darn square! And based upon the ASET image, I can tell you that the diamond exhibits an excellent degree of optical precision, because of how evenly light is being reflected throughout the diamond.

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Every princess needs a crown!

The importance of crown height on princess cut diamonds, James Allen SKU 581158, GIA 1203341314This is not typical of the majority of princess cut diamonds that I’ve evaluated over the years, Brian Gavin Signature Princess cut diamonds happen to be the most exceptional princess cut diamonds that I’ve ever seen. Naturally Brian Gavin relies upon a strict set of production parameters that ensures that the top and bottom halves of the princess cut diamonds they produce are evenly distributed, so that maximum light performance is achieved in accordance with the Light Performance grading standards of the AGS Laboratory. Take a look at the high resolution video provided on the diamond details page for this 1.045 carat, G-color, VS-1 clarity, Brian Gavin Signature Princess cut diamond and you’ll see that there is sufficient crown height (upper half) on the diamond, whereas most princess cut diamonds like this 1.00 carat, G-color, VS-2 clarity, princess from James Allen (left) offer very little in the way of crown height.

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The crown height on this particular princess cut diamond from James Allen is practically non-existent and I don’t like the fact that the table facet of 73% is larger than the total depth of 71.9% because this is likely to reduce the volume of fire and scintillation, thereby affecting the overall performance of the diamond.

Understand that I’m not saying that you can’t find a spectacular princess cut diamond from James Allen, merely that this is not a princess cut diamond that I would recommend. I selected this particular option from the virtual inventory of James Allen specifically because I feel that it lacks adequate crown height and wanted to demonstrate the effect that the pattern of chevron facets have upon a princess cut diamond.

This diamond is typical of what you’re likely to find in most high end jewelry stores, however there are better princess cut diamonds available from James Allen if know what to look for. The reality is that James Allen carries a broad selection of diamonds in a variety of cut qualities in an attempt to appeal to the largest market share possible. Whereas boutique operations like Brian Gavin Diamonds focus on providing diamonds of the highest cut quality, which are going to provide the highest volume of light return and sparkle factor.

Chevron facets make or break a princess cut diamond:

One of the reasons why Brian Gavin Signature Princess cut diamonds offer such spectacular visual performance is that he relies upon a three chevron facet structure, this article on the Effect of Chevron Facets on a Princess cut diamond light performance will explain why that is important. But it’s not just the number of chevron facets that makes the princess cut diamonds produced by Brian Gavin look so phenomenal, it is also that the pavilion main and chevron facets are all the same size, which evenly distributes the reflection of light throughout the diamond. Both this 1.00 carat, G-color, VS-2 clarity, GIA graded princess cut diamond from James Allen, and this 1.045 carat, G-color, VS-1 clarity, Brian Gavin Signature Princess cut diamond feature three chevron facets and one pavilion main facet:

The effect of chevron facets on princess cut diamond light return, comparison of three chevron facet designs

Clarity effect of chevron facets on princess cut diamonds, James Allen, SKU 581158, GIA 1203341314While both of the princess cut diamonds above feature three chevron facets, which are the chevron shaped facets that extend outward from the center of the diamond as indicated on the pavilion (bottom) view, which is the right side of each set of facet patterns pictured above; the one pictured to the left for the 1.00 carat, G-color, VS-2 clarity, GIA graded cut princess from James Allen will create a flat white region in the middle of the diamond in the form of an ‘X’ that I think interrupts the pattern of light return and creates a kind of dead zone in the stone. This is of course something which is a matter of personal preference, I have plenty of clients who seem to like the distinct visibility of the crystal clear X-pattern being visible in the middle of their princess cut diamond. Which is why these high resolution videos are helpful, they enable you to get an idea of how the different facet patterns of fancy shape diamonds affect the pattern that light reflects throughout the diamonds.

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Brian Gavin Signature princess cut diamond reviews, AGSL 104075727002As you can plainly see, the pattern of light distribution visible throughout this 1.045 carat, G-color, VS-1 clarity, Brian Gavin Signature princess cut diamond is different than the pattern of light being reflected by the princess cut diamond from James Allen referenced above. The distribution of light being reflected by this BGD Signature princess cut diamond is evenly distributed, because the pavilion main and chevron facets are relatively equal in width and the rest of the facets have been polished on to the diamond to the highest degree of optical precision. This is without a doubt an unfair comparison because the two diamonds are not of the same cut quality, they do not have similar proportions, and they are graded by two different gemological laboratories… but that also happens to be the point that I’m trying to make. There is a lot more to know about buying a fancy shape diamond besides the basic criteria established by the 4C’s of Diamond Grading.

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Cracking open the lid of Pandora’s Box:

Facet design plotting diagram round brilliant cut diamond, BGD Signature, AGSL 104080668006Buying a fancy shape diamond is a lot like cracking open the lid on Pandora’s Box, because when you embark on the quest to buy a fancy shape diamond, you really never know what to expect. Part of the reason is due to the vast variety of facet patterns that are commonly used to cut fancy shape diamonds. It is completely different when you set out to buy a traditional round brilliant cut diamond, because the facet structure of a classic round brilliant cut diamond is always going to look like the one pictured to the left for this 1.40 carat, K-color, VS-1 clarity, Brian Gavin Signature round hearts and arrows diamond. The facet structure of a modern round brilliant cut diamonds consists of 58 facets separated into four basic sections known as the Crown, Girdle, Pavilion and Culet. The crown section is the upper half of the diamond; the girdle is the line that separates the upper and lower halves of the diamond; the pavilion is the lower half; and the culet is the bottom point of the diamond. The facets are evenly distributed on the surface of the diamond, and the only variance might be if a cutter adds an extra facet to remove a surface inclusion.

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And then of course there is the matter of proportions, the manner in which the carat weight of the diamond is distributed between the three primary sections that comprise a modern round brilliant cut diamond. And the degree of optical precision that the diamond has been cut to exhibit, the consistency of facet shape and alignment, the consistency of facet size, and how precisely the facets have been indexed or polished on to the surface of the diamond and the degree of Azimuth Shift.

But everything is different when you’re shopping for a fancy shape diamond, because the pattern of facets that are polished on to the crown and pavilion sections of the diamond vary dramatically from stone to stone. Just take a look at this illustration that depicts fifteen of the most common pavilion facet structures for an oval brilliant cut diamond that I borrowed from the American Gem Society Laboratory list of supported shapes:

Variations pavilion facets oval brilliant cut diamonds, courtesy of AGS Laboratory

And there are different configurations of crown facet designs that can be used with them… Obviously each combination of different facet designs is going to produce a completely different look. The number of facets polished on to the surface of a diamond and the pattern by which they are configured, and even the size of the facets, will have a direct impact upon the visual  performance of the diamond.

A higher number of facets will break the reflections of light apart into smaller and smaller pieces, creating smaller virtual facets, which are the internal reflections of light created by the overlapping of facets and light being reflected into different size pieces as a result of those facets… Smaller sparkle tends to be interpreted by human eyes primarily as brilliance (white sparkle) instead of dispersion (colored sparkle) because of the manner in which our eyes clip the light, so this type of thing directly affects your appreciation of the fancy shape diamond that you buy.

Best places to buy fancy shape diamonds:

The internet is swarming with diamond dealers, most of which operate by simply mirroring the list of diamonds that appear on the Multiple Listing Service (MLS) that we subscribe to as trade members to market diamonds globally. A handful of companies like Enchanted Diamonds, James Allen, and Ritani, which work primarily off of this “virtual inventory of diamonds” provided via the MLS, have worked it out with their suppliers to be able to offer at least a clarity image of the diamonds. Sometimes a video and reflector scope images such as an ASET Scope, Ideal Scope, or Hearts and Arrows scope image might be available.

Does Blue Nile offer diamond clarity photographs? LD06196829, GIA 7203367064 via Nice IceBlue Nile offers the largest selection of GIA graded diamonds, primarily because they have secured the exclusive online representation rights to list the inventory of some of the largest diamond cutting houses in the world. However they generally do not provide any sort of images for diamonds that are not part of the Blue Nile Signature diamond collection. Thankfully I have been able to obtain clarity photographs and reflector scope images for many of the diamonds that my clients have expressed an interest in, so it’s worth asking me to assist you with your diamond quest. I can not promise that images will be available for the diamond that you are interested in, but they seem to be about 50% of the time. For instance, there was a clarity photograph and an ASET scope image available for this 1.20 carat, E-color, VVS-1 clarity, GIA Excellent cut oval brilliant shape diamond from Blue Nile when I looked it up on the MLS. The crown height (13.7%) and pavilion depth (43%) measurements were also provided, which are not provided on GIA diamond grading reports for fancy shape diamonds.

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With this information in hand, we’re able to take a look at the proportions chart for oval brilliant cut diamonds and determine that this diamond with a total depth of 59.7% and a table diameter of 55% and a crown height of 13.7% with a medium to slightly thick girdle and a length to width ratio of 1.44:1.00 falls within the specifications suggested for the Class 1A Ideal Cut proportions rating on the legacy proportions chart for oval shape diamonds created by Gemologist David Atlas. Thus we can be relatively confident that this diamond is going to exhibit a high volume of light return, and it features a classic oval facet structure which should provide sparkle that is larger in size, just the type of thing that I look for in an oval brilliant cut diamond.

Best place to buy square hearts and arrows cushion cut diamonds online, Brian Gavin, AGSL 104066027014Now if you’re looking for a princess cut diamond or a square cushion brilliant cut diamond, then you owe it to yourself to check out the Signature Princess cut diamonds from Brian Gavin, and the Brian Gavin Signature Cushion cut diamond. Both of which offer mind blowing broad spectrum brilliance (white sparkle) and dispersion (colored sparkle) with the highest volume of light return! In addition to producing some of the most spectacular princess and cushion cut diamonds that I’ve ever seen, the diamond details pages provided by Brian Gavin feature a high resolution video of the diamonds, as well as a clarity photograph, and an image of the diamonds as seen through an ASET Scope, an Ideal Scope, and a Hearts & Arrows scope where applicable. Such as in the case of this 1.208 carat, E-color, VVS-2 clarity, Brian Gavin Signature Cushion cut diamond which exhibits hearts and arrows when viewed from the pavilion side using a special reflector scope that colors the diamond red.

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Victor Canera Antique Cushion cut diamond:

Victor Canera antique cushion cut diamond reviews, AGSL 1417200107This 2.211 carat, H-color, VS-1 clarity, antique cushion cut diamond by Victor Canera is graded by the AGS Laboratory with an overall cut rating of AGS Ideal-0 and is perfect if you’re looking for more of that vintage look in a diamond, but also want the best in light performance. I’m sure that by now you realize that cushion cut diamonds are also produced with a myriad of facet structures, all of which produce a different look. It’s really all about discovering which pattern of light return appeals to your personal sense of style, but be sure to check out the ASET scope image for this diamond, all that red indicates it’s super bright!

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Victor Canera European cut diamond:

Victor Canera European round diamond reviews, AGSL 1429380590Victor Canera also produces the Canera European round cut diamond which is a modern variation of the old European round cut diamond. It’s not really a fancy shape diamond, but it’s worth checking out if you’re looking for something different than a modern round ideal cut diamond. As you can see the pattern of light return and contrast exhibited by this 1.95 carat, I-color, VS-2 clarity, Canera European round cut diamond is dramatically different than a modern round brilliant cut diamond. ASET Scope and Ideal Scope images are provided on the diamond details pages for all Victor Canera diamonds.

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Which diamond shape is the most popular?

In case you’re wondering what the most popular shape diamond happens to be, the modern round brilliant cut diamond remains the most popular. However princess and cushion cut diamonds are also extremely popular. This graphic provided by Ritani reflects the percentages of orders for fancy shape diamonds ordered by their clients.

What is the most popular diamond shape, courtesy of Ritani

The best way to buy a fancy shape diamond:

As you can plainly see, there is a lot more to consider when buying a fancy shape diamond than just the basic Diamond 4C’s might lead you to believe. It’s always a good idea to learn as much as possible before making a major purchase such as a diamond, but the reality is that it can take a lot of time to fully understand the subtle intricacies that distinguish different facet designs from another. Which is why you should consider taking advantage of my free Diamond Concierge Service when shopping for a fancy shape diamond. This October I will celebrate my 30th year working in the diamond business as a professional diamond buyer, and I’ve got the filters in place to conduct searches rapidly and effectively for diamonds of all shapes and sizes. Use the form referenced above to send me a search request, please include the desired shape, range of carat weight, clarity, color, blue fluorescence, and price range that you are willing to consider.

People often inquire as to how my Diamond Concierge Service can be free, after all I have to earn a living somehow, right? The reality is that I generate referral fees from various vendors promoted on this web site when you buy a diamond using the links provided herein or via email. The exciting part is that your price on the diamond is going to be exactly the same whether you buy the diamond using the affiliate link provided, or if you were to find the diamond yourself by searching their web site. However when you work with me, the odds of your finding a truly exceptional diamond are greatly improved.