This in-depth oval diamond buying guide will make it easier for you to buy an oval brilliant cut diamond. In the first place, we're going to talk about the Pros and Cons of the oval cut facet structure.
Secondly, we're going to look at the role that proportions play in the sparkle factor and performance. We're also going to show you how the many different facet patterns of oval cuts affect light performance.
At the same time, we're going to look at how the lighting environment can affect our perception of beauty. By the time you finish reading this article, you'll be able to buy an oval cut diamond with confidence.
Oval Cut Diamond Buying Tips:
The most common mistake people make when buying a diamond is assuming that the cut grade reflects performance. In reality, the overall cut grade of a diamond is only the first piece of the puzzle.
In other words, an overall grade of AGS Ideal or GIA Excellent is only the beginning. To begin with, the GIA does not issue an overall cut grade for fancy shape diamonds.
That means that there is no such thing as a GIA Excellent Oval-cut diamond. Take this oval-shaped diamond from Blue Nile, for example. The polish and symmetry grades are excellent, but there is no overall cut grade on the report.
Crown/Pavilion Measurements = Performance:
The GIA does not provide the crown and pavilion measurements on diamond grading reports for fancy-shaped diamonds. Consequently, the crown and pavilion measurements are essential to predict light performance. Without that information, you cannot estimate the balance of brilliance, dispersion, or light return.
Although it seems counterintuitive, the symmetry grade on the report does not account for optical precision. That is the consistency of facet shape, size, and alignment from the perspective of 360-degrees.
An ASET map may be available if the AGS grades the diamond on the Light Performance grading platform. Otherwise, you'll need an ASET Scope to verify light performance and see whether light reflects evenly.
GIA Excellent Oval Cut Diamonds:
In the first place, there is no such thing as a GIA Excellent Oval-cut diamond. As stated previously, the GIA does not issue an overall cut grade for fancy shape diamonds.
Secondly, the diamond proportions dictate the volume of light return and sparkle factor. Specifically, the pavilion angle affects the amount of light return. At the same time, the crown angle determines the balance of brilliance and dispersion.
In other words, the crown height will determine the balance of white and colored sparkle/fire. It is impossible to estimate the light performance without the crown/pavilion angle measurements.
Simultaneously, it is challenging to predict fancy diamond shapes' light performance because the facet structure is not symmetrical. In comparison, the facet pattern for a round brilliant cut diamond is uniform.
Under those circumstances, the facets are going to reflect light more evenly. On that note, the difference in the crown and pavilion facets' length creates the bowtie effect. That's because the light's size reflecting off the parts is different due to the facet size.
Although that might be true, the proportions of an oval shape diamond will also affect the bowtie's visibility. With that in mind, we recommend that you adhere to the following measurements if you want a spectacular l looking oval diamond.
Best Proportions for Oval Diamonds:
Be forewarned that it is challenging to find oval cut diamonds within this range of proportions. In the first place, the majority of diamond cutters focus more on the retention of carat weight.
Secondly, it costs more to cut diamonds to these proportions because it results in a more significant loss of rough material. It can also take up to 4X longer to polish diamonds to exhibit a higher degree of optical precision.
AGS Ideal Proportions for Oval Cuts:
Unlike the GIA, the American Gem Society Laboratory (AGSL) does issue an overall cut grade for fancy-shaped diamonds. The AGSL also provides the crown and pavilion measurements on their lab reports.
At the same time, I prefer the insight that the AGSL proprietary light performance grading platform provides. After all, the lab report's ASET map enables us to determine how evenly light reflects throughout the diamond.
Be that as it may, you're not likely to find an AGS Ideal Oval Cut Diamond. From the diamond cutter's perspective, it's already difficult enough to produce ideal cut round diamonds. Fewer than 1% of the annual production meets our proportions criteria.
Once again, I'll remind you that the shape of a round diamond is perfectly symmetrical. Whereas an oval brilliant-cut diamond is, well, oval-shape, and therein lies the rub. It's next to impossible for most diamond cutters to consistently hit the light performance mark with fancy-shaped diamonds.
Be that as it may, I'm hopeful that fifth-generation diamond cutter Brian Gavin might one day rise to the challenge. After all, he is the only diamond cutter globally with a patent for maximizing light performance in the modern round brilliant cut diamond. He also holds patents for two AGS Ideal-0 fancy shape diamonds:
Unfortunately, I don't think that Brian Gavin has plans to create an ideal oval diamond any time soon. After all, it's difficult enough to find the right rough to produce his patented cushion and emerald-cut diamonds.
AGA Oval Proportions Chart:
The AGS Laboratory does not publish the proportions criteria for oval brilliant-cut diamonds. With that in mind, there is no way of knowing the AGSL proportions for an oval ideal cut diamond.
However, the proportions chart for oval cut diamonds created by David Atlas of Accredited Gem Appraisers (ASA) is a good starting point. It is the proportions chart that I relied upon when I was the diamond buyer for Nice ice. At that time, I would use this chart as a guideline while searching for oval shape diamonds.
Adhering to these proportions makes it easier to narrow down the options and improve your chances of success. Of course, it's important to remember that the proportions are only one piece of the puzzle. Under those circumstances, you should also know how to use an ASET Scope to judge light performance.
I recommend that you adhere to the recommendations for the Class 1A Ideal Cut and 1B Premium ratings. The lowest range that I would be willing to consider is the range of Class 2A-2B International Fine Trade Cut.
Crown/Pavilion Angle Measurements:
In the first place, a round brilliant cut diamond and an oval are completely different diamond shapes. Simultaneously, there are some similarities in the basic facet structure of round and oval shape diamonds.
With that in mind, it seems reasonable that we can use our understanding of light performance in round diamonds as a foundation upon to build.
We know that the ideal pavilion angle for a round brilliant cut diamond is 40.6 - 40.9 degrees. Consequently, a pavilion angle within that range will produce the highest volume of light return. The most compelling evidence suggests that the light return decreases when the pavilion angle is beyond that range.
A crown angle between 34.3 - 35 degrees will simultaneously produce a virtual balance of brilliance and dispersion. In other words, a round brilliant cut diamond is likely to exhibit a balance of white and colored sparkle/fire when the crown angle is between 34.3 - 35 degrees.
Consequently, if the crown measurement is higher or lower, then the degree of brilliance and dispersion will be off-balance. Although this may be true, there are distinct differences between a round and oval diamond.
In the first place, the outline of the two diamonds is entirely different. However, the basic facet structure of the shapes is practically identical. As such, you're going to find it necessary to expand the range of proportions for oval cut diamonds.
Crown Height and Sparkle Factor:
A crown angle below 34.2 degrees is likely to produce more brilliance, but it will be at the expense of dispersion. Likewise, a crown angle steeper than 35.3 degrees should create more dispersion. However, it will be at the cost of brilliance.
The steeper crown angle is also likely to make the diamond appear dark and dead in the middle when viewed under diffused light. Since most of us live and work under diffused lighting in this modern age, that's a bad thing.
With this in mind, we strongly suggest a crown height of 12 - 15% for oval shape diamonds. Consequently, you might notice that a crown height of 16% or more tends to make oval brilliant cut diamonds look dark. Whereas a crown height less than 11% is likely to create more brilliance and less dispersion.
That is a challenge since the GIA does not provide the crown/pavilion measurements for fancy-shaped diamonds. With that in mind, the best way to determine the crown height is computer proportions analysis. However, this might not be an option. In which case, it helps to know how to estimate the crown height of a diamond visually.
The Oval Diamond Bowtie Effect:
One of the first things that people tend to notice when they look at oval shapes is the bowtie effect. In the first place, you'll find that all oval cut diamonds exhibit a bowtie effect to varying degrees. The difference in contrast of the light reflecting in different sizes and shapes creates the bowtie effect.
To be more specific, the difference in the lower girdle facets' length produces reflections of different sizes. The differences in the facet structure also create varying degrees of contrast brilliance. The plotting diagram on the left demonstrates how the facet structure creates the bowtie effect.
The effect of the crown/pavilion angle measurements can also warp how light reflects through the diamond. In which case, the facet structure and proportions can influence the intensity of the bowtie effect.
By the way, the facet structure shown is for a modified oval brilliant cut diamond. If you scroll back up the page, you will see how this varies from the traditional oval cut diamond.
That brings us to the next point: How does the facet structure of an oval brilliant-cut diamond affect the sparkle factor? And what is the best facet structure for an oval cut diamond?
Suffice to say that a modified oval cut diamond is not necessarily better than a traditional oval shape. Consequently, the decision to purchase one style of oval over another is mostly a matter of personal taste.
Oval Diamond Facet Structures:
In the first place, it is essential to remember that oval cut diamonds are available in many different facet patterns. With that in mind, the overall appearance of oval shape diamonds can vary dramatically. In other words, the facet pattern of an oval diamond can change the look entirely.
For one thing, the number of main pavilion facets can affect the sparkle's size and intensity. Of course, the facet pattern is also going to affect the appearance of the bowtie effect. It's a good idea to familiarize yourself with an oval cut diamond's different facet structures under those circumstances.
How Many Facets in an Oval Cut Diamond?
The traditional oval cut diamond has 58 facets including the bottom point that is the culet. As a matter of fact, the facet structure of an oval shape diamond is similar to the modern round brilliant cut diamond.
The basic structure of the two diamond shapes is the same, but the shape of the outline is different. For this reason, the facets on an oval diamond are not symmetrical in shape per section. In other words, you will notice that the facets within each group vary in size and shape.
Crown Facet Structure:
The crown facets of an oval brilliant cut diamond consist of the table facet, star, bezel, and upper girdle facets. With exception of the table facet, the other sections can be divided equally by eight. To be more specific, there is one table facet, eight star facets, eight bezel facets, and sixteen upper girdle facets.
(1) Table Facet: The large flat facet that appears on top of the crown section is the table facet. We recommend keeping the table facet of a round diamond between 53 - 58% for optimum performance.
(8) Star Facets: The triangle shaped facets that border the table facet are the star facets. If you look closely, you will notice that the star facets are different sizes and shapes.
(8) Bezel Facets: The kite-shaped facets that connect the table facet to the girdle edge of the diamond are known as bezel facets. Some people also refer to the bezel facets as kite facets since the outline is kite-shape. Here again, you will see that the bezel facets of an oval diamond are not uniform in size and shape.
(16) Upper Girdle Facets: The elongated triangle-shape facets that border the edge of the crown section are called upper girdle facets. In order for light to reflect evenly throughout these facets, it is important that the crown angle and crown height measurements are cohesive. Once again, notice that the size and shape of the upper girdle facets is not uniform.
Pavilion Facet Structure:
The pavilion facets of an oval cut diamond consist of the eight pavilion main facets that create the arrows pattern. Along with sixteen lower girdle facets that are located between the pavilion main facets.
(8) Pavilion Main Facets: The arrows pattern or 6-8 pointed star that you see when looking at an oval diamond in the face-up position is created by light reflecting off of the pavilion main facets.
(16) Lower Girdle Facets: There are eight pairs of lower girdle facets within the pavilion section of an oval shape diamond.
Interestingly enough, the lower girdle facets play an integral part in creating hearts patterns in round brilliant cut diamonds. Basically, the light reflecting off the lower girdle facets splits apart across the pavilion main facets into two sections that eventually form a heart as shown in the photograph to the left.
However, it is not possible to create the same optical phenomena in oval cut diamonds because the size and shape of the lower girdle facets is not uniform. Under those circumstances, the flashes of light reflecting off the facets vary in size, shape, and intensity. As a result, you will find that most oval cut diamonds exhibit uneven patterns of light reflecting within the diamond.
4-Pavilion Main Oval Cut Diamond:
One of the most common variables that you will encounter in oval cut diamonds is the different in the number of pavilion main facets. As an illustration of that fact, we're going to highlight the pavilion main facets in green throughout the next few sections.
In the first place, you'll want to pay attention to the number of pavilion main facets that create the star pattern. Secondly, you'll want to take note of the size and shape of the pavilion main facets.
The combination of these two factors will affect the sparkle factor. In addition, if you click on the links provided, you'll be able to see how each of these options reflects light differently.
This 1.01 carat, D-color, VS-1 clarity, oval cut diamond from Blue Nile features 4-pavilion main facets. Be sure to watch the 360-degree video on the diamond details page and notice how light reflects throughout the diamond.
Then, click on the photograph of the diamond located to the left of the video frame. That will enable you to view the diamond in the face-up position and judge the bowtie effect.
Generally speaking, it seems like this facet structure produces big, bold flashes of light. At the same time, the sparkle is similar to the flat sparkle that you will see reflecting off the surface of a shallow fish pond.
6-Pavilion Main Oval Cut Diamond:
This 1.01 carat, E-color, VVS-1 clarity, oval brilliant cut diamond from James Allen features a 6-pavilion main facet structure. Click the link above to go to the diamond details page where you can view the high-resolution video.
Once there, you can left click and hold down the button on your mouse to move the diamond left and right. From that vantage point, you will be able to identify the six pavilion main facets.
In the first place, this is a good habit to get into because it enables you to see how light reflects off the facets. Secondly, it will enable you to judge the degree of the bowtie effect from different vantage points.
Generally speaking, I find that oval diamonds with 6-pavilion main facets produce mid-to-large size sparkle that is vivid and intense.At the same time, the bowtie effect can be more pronounced because of the arrow in the middle.
Obviously, this is something that you will need to consider on a stone-by-stone basis. That is because every oval cut diamond is going to face-up differently as a result of the proportions and individual nature of the facet structure.
8-Pavilion Main Oval Cut Diamond:
The plotting diagrams on the left shows a traditional oval cut diamond with 8-pavilion main facets. Although this may be true, you will notice that the 8-pavilion main facets are configured differently.
Obviously, the light will reflect differently throughout these diamonds as a result of that fact. At the same time, the bowtie effect exhibited by these diamonds will also be different.
In the first place, the light will reflect differently as it splits across the facets. Secondly, the shape of the bowtie effect will be affected by the facet structure.
As a matter of fact, this 1.01 carat, F-color, VVS-1 clarity, oval diamond from James Allen features the 8-pavilion main facet structure shown on the far left. While this 1.00 carat, G-color, VVS-2 clarity, oval cut diamond from Blue Nile features the 8-pavilion main facet structure shown above.
If you look at the video for the 8-pavilion main oval cut from James Allen, you'll see that the pavilion main is clearly visible in the middle of the stone. Whereas the slightly different 8-pavilion main facet structure of the one from Blue Nile leaves the center section feeling more open.
Consequently, my personal preference is the eight-pavilion main facet structure on the right. That's because it tends to produce less of a bowtie effect while making the diamond seem brighter. Whereas having the pavilion main in the middle seems to create too much contrast in all the wrong areas.
Although this may be true, it is also important to remember that this is my personal preference. Obviously, you need to base your selection criteria on your own expectations, needs, and preferences.
Optical Precision = Light Performance:
As a matter of fact, the importance of optical precision is probably the least understood factor of diamond light performance. In the first place, optical precision is simply the consistency of facet shape, size, and alignment from the perspective of 360-degrees. In other words, it is the consistency and precision of the facet structure.
Oval Diamond ASET Scope:
The supplier of this 1.02 carat, G-color, Internally Flawless, oval brilliant cut diamond from Blue Nile provides the images necessary for us to judge optical precision. Specifically, they provide the ASET Scope image on the left and the Ideal Scope image shown below.
Understanding how to use the ASET Scope to judge light performance will help you choose a better looking diamond. In the first place, the ASET Scope makes it possible for you to see how evenly light is reflecting throughout the diamond.
Secondly, the ASET Scope shows us where in the hemisphere this oval cut diamond is gathering light from. That's what the colors red, green, and blue are meant to signify, but I'm more interested in whether or not the light is being distributed evenly.
At the same time, this ASET Scope image shows where the diamond is leaking light. As a matter of fact, all of that transparent white space is light leakage. Be that as it may, this high degree of light leakage is pretty typical for oval cut diamonds.
The Ideal Scope image 1.02 carat, G-color, Internally Flawless, oval brilliant cut diamond from Blue Nile shows a moderate amount of light leakage. As a matter of fact, that is what all of the transparent and light pink sections represent.
Although this may be true, it's also important to realize that this level of performance is typical of most oval cut diamonds. In other words, the amount of light leakage shown in this Ideal Scope image meets with my expectations for this diamond shape.
With that in mind, I'm more interested to see how evenly light appears to be reflecting throughout this diamond. For the most part, it seems to me that light is reflecting pretty evenly throughout this oval cut diamond. Therefore, it seems like a pretty good choice.
Of course, ASET and Ideal Scope images are not available for the majority of oval cut diamonds. Obviously, that presents a bit of a challenge because it essentially means that you're buying blind. Be that as it may, it's worth asking me whether images are available because sometimes they are.
Oval vs. Brian Gavin Cushion:
In the first place, I want you to know that I'm not trying to talk you out of buying an oval cut diamond. As a matter of fact, I'll help you find an oval cut diamond if that's what you really want.
At the same time, a lot of people buy oval cut diamonds simply because they want something other than round. In which case, you might want to explore other options like the Brian Gavin Signature Cushion cut diamond.
After all, the ASET Scope featured above shows a high volume of light return and virtually no leakage. At the same time, the ASET Scope shows that light is reflecting evenly throughout the diamond. The hearts pattern on the right is an illustration of that fact because it reflects the highest degree of optical precision.
As a matter of fact, each one of those hearts consists of two halves. In other words, the light reflecting off two lower girdle facets joins together to create one heart. Any deviation in the size and shape of the lower girdle facets will result in the hearts being uneven and the tips of the hearts will bend. You'll never see this sort of thing in an oval cut diamond because the facet structure lacks symmetry.
Where to Buy Oval Brilliant Cut Diamonds:
In our experience, the best places to buy oval cut diamonds are the vendors we have chosen to work with. That is because these vendors strive to provide our clients with the best overall selection and experience.
In the first place, you're going to want to set the total depth between 59 - 63%. Secondly, you'll want to set the table diameter so it's between 55 - 60%. Then be sure to adjust the sliders to polish and symmetry are both excellent. That's because the odds of your finding oval cut diamonds with better performance increase dramatically under those circumstances.
Oval Diamond Carat Weight Chart:
This diamond carat weight chart from Blue Nile provides a visual reference of the most popular diamond shapes and sizes. That means that you will be able to see the difference between a 1.00 carat round and oval cut diamond for example.
Consequently, you might have heard that oval diamonds cost less than round brilliant cut diamonds. Although that may be true, it is also kind of an oversimplification of the concept.
In the first place, round and oval cut diamonds are usually cut from different types of diamond rough. As a matter of fact, the rough material reserved for rounds is more expensive because it is more uniform in shape.
In addition, oval cut diamonds are cut longer and can be shallower than round brilliant cut diamonds. This spreads the weight out differently across the finger, but also affects the sparkle factor and light performance.
Under those circumstances, the odds of an oval cut diamond exhibiting the same sparkle factor of an ideal cut round is slim to none. Although this may be true, it's also fair to assume that most people buy an oval cut diamond because they prefer that shape.
Round vs. Oval Shape Diamond Prices:
As can be seen by the examples below, there is a difference in the Price Per Carat (PPC) of round and fancy shape diamonds. At the same time, it is often necessary to purchase a larger fancy shape in order to achieve the same relative size as a round diamond on the finger.
At the same time, there tends to be a distinct difference in the degree of light return and sparkle factor. It doesn't take a rocket scientist to see that the sparkle factor of the James Allen True Hearts round diamond is going to be more vivid and intense than the cushion and oval brilliant cut diamonds.
One of the reasons for the difference in light performance is that the facet structure of round diamonds is more symmetrical. At the same time, the majority of fancy shape diamonds exhibit higher degrees of light leakage. That is because they are generally not cut to exhibit the higher degree of optical precision as hearts and arrows diamonds.
Consequently, all of the diamonds listed above have proportions within our preferred range. The supplier for the oval cut diamond states that the crown height is 15.5% which puts it in the range of AGA 1B Premium Cut. The oval cut diamond is listed by both Blue Nile and Ritani at different prices. Although that is not necessarily an issue since Blue Nile will price match in this type of situation.
The GIA Excellent cut round diamond is a good comparison for price because it is not hearts and arrows. As a matter of fact, hearts and arrows round diamonds cost more than standard ideal cut diamonds because it can take up to 4X longer to create the higher degree of optical precision.
The Best Settings for Oval Diamonds:
In the event that you've got your heart set on an oval diamond engagement ring, you're in luck because there is a plethora of settings to choose from. As a matter of fact, every ring style that is available for round diamonds is generally available for oval cuts from:
Petite Solitaire for Oval Diamonds:
In the first place, the most popular engagement ring of all time is the traditional solitaire. With that in mind, I'm definitely a fan of the petite solitaire from Blue Nile. As a matter of fact, I think it is one of the prettiest solitaire style engagement rings for oval cut diamonds.
As can be seen, the petite solitaire is a modern twist on the traditional solitaire engagement ring. In that case, it's perfect for people who prefer traditional style rings, but want something a little more modern.
Of course, the petite pavé setting is available from Blue Nile with diamonds set in the shank if you want something with more sparkle.
Halo Settings for Oval Cut Diamonds:
As a matter of fact, I ran across this halo setting while flipping through Instagram the other day. I love the way that the halo setting makes the diamond look bigger.
Of course, I was also drawn to the beautiful beach and ocean in the background. Let's be honest, there is just something about photographs of engagement rings on the beach that attracts my attention.
After all, diamonds and the beach are two of my favorite things! As it so happens, this halo setting was custom designed by Brian Gavin. The center stone is a 2.50 carat, F-color, VVS-2 clarity, oval cut diamond. Obviously, it's a total stunner and the halo setting makes it look even more so.
I can only imagine how blindingly beautiful that oval diamond ring looks in the sunlight. Obviously, Kris and Nicole took this photograph while standing under the shade of a palm tree.
That is one of the best places to photograph diamonds by the way. Well, not specifically while standing under a palm tree, although that works for me. But rather, while standing underneath the shade of a tree.
That's because the leaves of the tree will provide some shade while letting just enough sunlight peek through to make the diamond sparkle. Otherwise what happens is your eyes will adjust to protect themselves from the brightness and the diamond will look dark and grey-blue color.
Pavé Setting for Oval Diamonds:
Pavé settings are one of the most popular styles of engagement rings. At the same time, pink rose gold settings have been enjoying a new era of popularity. With that in mind, this 14k rose gold pavé setting from James Allen is bound to be a popular choice!
Of course, this ring style is available in all the popular alloys, such as platinum, rose gold, white gold, and yellow gold. There is also a flush fit matching band available, but this is the one pictured.
I actually think that this engagement ring would look pretty cool with a contoured band on both sides. Another option that I really like is this 14k rose gold halo setting from James Allen.
I should also mention that setting a diamond in a rose gold setting will make it seem about one color grade warmer. In other words, setting an I-color diamond in rose gold is going to make it seem more like J-color.
Of course, the reverse is true and setting an I-color diamond in white metal will make it seem more like H-color. That's because the color of the metal touching the edge of the diamond will reflect throughout the stone and affect our perception of diamond color.
French-set Halo for Oval Diamonds:
As a matter of fact, the French Halo Setting by Ritani is extremely popular with my clients. People love how the diamond halo makes the center stone seem larger and creates more sparkle on their hand. At the same time, the setting is comfortable and light weight.
The three row pavé halo setting from Ritani is another popular choice. The primary difference between the two halo settings is that the 3-row has diamonds set across the top of the ring shank and on the sides.
People often ask me what is a pavé setting. As a matter of fact, the term pavé refers to the manner in which the diamonds are set in the ring. In the first place, the jeweler will create the seats for the diamonds. Then, the jeweler will push little shavings of metal up from the ring and over the edge of the diamond.
As a matter of fact, the very nature of pavé settings makes them delicate and we would never recommend wearing an engagement ring in the pool. But hey, it makes for a great picture, doesn't it?
Monique Lhuillier Engagement Rings for Oval Cuts:
Be sure to check out the Monique Lhuillier Collection from Blue Nile if you're looking for designer settings for oval cut diamonds. This collection of engagement rings for round diamonds contains a lot of very pretty designs.
Consequently, a lot of them are available for oval shapes. That means that you're likely to find something different than the usual choices.
Of course, there is an extensive catalog of settings for oval cut diamonds on Blue Nile. These just happen to be some of the more popular styles from designer Monique Lhuillier. This is just an illustration of some of the settings that are available.
Be sure to take advantage of our Free Diamond Concierge Service regardless of where you decide to purchase your engagement ring. We're happy to put our diamond expertise to good use and help you search for oval cut diamonds.