Oval Cut Diamond Buying Guide (Everything you need to know!)

Buying an Oval Cut Diamond can be challenging, with lots of “information” out there but this guide will make things a lot clearer!

Whether you are buying for an engagement ring or piece of jewelry, you want to buy the best Oval Cut Diamond you can and that is what I will cover in detail.

First off, who am I to give this information? I’m Paul Haywood FGA DGA and I’m a fully qualified gemologist with over a decade’s worth of experience in the industry, 7 years of which were running my own online retailer.

Quick Summary

Don’t want to read the whole post? Don’t worry, I’ve summarized it for you below:

  • Color – If you want a colorless Diamond, then an F, G or H offers this without the premium of a D or E color stone
  • Clarity – A VS1 or VS2 Diamond won’t have any visible inclusions to the naked eye and you can get some very clean-looking SI1 stones, avoid I clarity Diamonds
  • Cut – Oval cuts aren’t cut graded but avoid stones with an obvious ‘bow tie’ effect, go for stones with an Excellent or Very Good Symmetry and Polish grade and avoid stones with Very or Extremely Thick girdle
  • Fluorescence – not as big of an issue as made out to be, only a small number of Diamonds with very strong fluorescence will have an undesirable milky appearance
  • Reports – often called certificates, best to go for a Diamond with a report from a reputable gem lab such as the GIA or IGI

Oval Cut Diamond Color

The first of the 4 C’s I’m going to look at for Oval Cut Diamonds is Color and one of the good things about Oval Cuts is that the way the facets are arranged on the stone, they are quite forgiving when it comes to color.

If you want a colorless Oval Cut, then I would recommend going for an F, G or H color as they are all colorless when viewed table up but don’t attract the premium of a D or E color (which just look a bit brighter).

For Ovals weighing more than 2 carats, some H colors may show a small hint of color and you may be best going for a minimum of a G color.

I color oval cut Diamond
I Color Diamond
G Color Oval Cut Diamond
G Color Diamond
E Color Oval Cut Diamond
E Color Diamond

Most people only start to notice a hint of color in the stone at an I grade and as you move further along the scale, this tint becomes much more notable.

In terms of prices, D and E color Diamonds attract a premium as they are rarer but for those shopping to a budget, an F, G or H will get you a nice, colorless Diamond and it would take a trained Diamond grader to be able to tell the difference, especially when the stone it set.

If you are wondering what the difference is between D – G color Diamonds if they are all colorless? Simply, it is how ‘bright’ the stone is and this is hard to show on a screen.

Obviously, if you have the budget or just want a stone you can brag about, then go for a D Color Diamond.

Oval Cut Diamond Clarity

The second of the 4 C’s is Clarity and another important aspect of buying a Diamond.

As with color, the way the facets are done on Oval Cut, they are very forgiving when it comes to clarity as they can make inclusions look less obvious than in some other styles of cut.

For most people, I recommend going to for a VS1 or VS2 clarity stone as the inclusions won’t be visible to the naked eye (and are in some cases difficult to spot under magnification) but they don’t attract the premium that a VVS will.

A SI1 Clarity Oval Diamond
A VS1 Clarity Oval Cut Diamond
A VS1 Clarity Oval Diamond
A VVS1 Clarity Oval Cut Diamond
A VVS1 Clarity Oval Diamond

Good SI1 clarity stones are also worth considering but I would avoid stones where the inclusions is under the table as these are much more noticeable, when the inclusions are under the crown facets, SI1’s Diamonds can be a great buy.

I always recommend avoiding I clarity Diamonds as their inclusions not only affect the beauty of the stone but can also compromise its durability.

And as with color, if you have the budget or want a stone to really brag about, then go for a Flawless Diamond.

Top Tip: If you are browsing Diamonds online, remember that they are magnified and under optimal lighting and even though an inclusion may look big/obvious on the picture, that may not be the case when looking at the Diamond in person.

Oval Cut Diamond Cut Quality

Unlike Round Brilliant Cut Diamonds, Oval Cut Diamonds aren’t graded for their cut quality by gem labs such as the GIA or IGI and this does make the buying process a little more challenging.

But there is one big thing you need to be aware of when it comes to Oval Cuts and that is what is known as the ‘bow tie’ effect, which is a dark area across the center of the Diamond that looks like a bow tie.

Oval Cut diamond with bow tie effect
An Oval Cut Diamond with an obvious bow tie effect
An Oval Cut Diamond with subtle bow tie effect
An Oval Cut Diamond with a subtle bow tie effect

Due to the way Oval Cut Diamonds are cut, they all have a bow tie to some degree but like in the images above, it can be very obvious in some stones and very subtle or barely noticeable in others.

The best way to check whether the stone has a bow tie effect is simply by looking at the stone as even stones that fall within so-called ‘ideal’ proportions can still show an obvious bow tie.

But there are some things when it comes to cut that you need to know about with Oval Cut Diamonds and I’ll cover these below:

1. The Length-to-Width Ratio

Contrary to what many people say, the length-to-width ratio doesn’t have a big impact on the bow tie effect as there are many Diamonds that fall in the ‘ideal’ range of 1.30 to 1.50 that display an obvious bow tie and ones that are outside of this range, like in the image below.

Oval Cut diamond with bow tie effect
An obvious bow tie in an Oval Diamond with a length-to-width ratio of 1.42
Subtle bow tie effect in a Diamond with a 1.65 length to width ratio
A very subtle bow tie in an Oval Diamond with a length-to-width ratio of 1.65

The length-to-width ratio of the stone you buy should come down to personal preference, but as a guide:

  • Less than 1.30 – these will have a more rounded shape
  • 1.30 – 1.50 – these will have a traditional oval shape
  • Greater than 1.50 – these will have a more elongated shape

2. Total Depth Percentage

This is quite an important one as the total depth percentage is closely related to the angle of the pavilion facets, which has a big impact on the bow tie effect as:

  • A stone with a shallow pavilion angle is more likely to have a strong bow tie
  • A stone with a steep pavilion angle is less likely to have a bow tie but the stone can look dull and lifeless

Unfortunately, the pavilion angle isn’t something that is listed by Diamond retailers but they do list the total depth percentage and a range of 58%-62% is good to go for but it still isn’t a guarantee that the stone won’t have a bow tie.

3. Table Size

Diamond cut proportions - table size

The table size doesn’t have a big impact on the bow tie effect but it does impact on how light interacts with the Diamond and affects the amount of fire and brilliance to stone shows.

An ideal table size is between 53% and 63% of the total length of the Diamond as this should give a good balance between the amount of fire and brilliance the stone shows, meaning that it should sparkle the way a Diamond should.

4. Symmetry

This is something that is graded by gem labs and is important in Oval Cut Diamonds.

If you aren’t sure what I mean by symmetry, imagine putting a line down the center of the stone and checking to see that both sides look the same.

And I always recommend going for an Excellent or Very Good Symmetry grade as this ensures that the stone has a nice, even outline and good symmetry does also have an impact on the bow tie effect as it can be more pronounced in stones with poor symmetry.

As a second to this, I would also recommend buying a Diamond with an Excellent or Very Good polish grade.

5. Girdle Thickness

Girdle thickness is also something you want to pay attention to and ideally you want to buy a Diamond with a Thin, Medium or Slightly Thick girdle as it provides enough durability without paying for additional weight.

Extremely or Very Thin girdles can have durability issues as the very thin edge can get chipped quite easily, which isn’t ideal, especially for a stone that is going in an engagement ring.

Thick to Extremely Thick girdles add additional weight to the Diamond but without that size of the stone getting any bigger.

Oval Cut Carat

The weight of the Diamond you buy is going to depend on your budget and generally, the more the stone weighs, the more expensive it will be but one thing to be aware of is that the weight of a Diamond doesn’t directly correlate to size.

And even though there are charts out there, such as my Oval Cut Size to Weight chart, these should only be used as guides as the proportions vary from stone to stone, meaning two stones can have the same length and width but slightly different weights.

0.5 Carat = 6.5 x 4.4mm

0.75 Carats = 7.2 x 5.1mm

1 Carat = 7.8 x 5.7mm

2 Carat = 9.4 x 7.4mm

3 Carat = 10.6 x 8.5mm

The images above aren’t to scale as this is very difficult to do with different sizes screens and resolutions!

Due to their elongated shape, a well cut 1 carat Oval Cut will look bigger than a 1 carat Round Brilliant and this means that they are definitely worth considering for people who want more presence from their Diamond.

And the elongated shape means that they can be great option for people with longer fingers.

Fluorescence

Possibly the most misunderstood (and sometimes mis-sold) aspect of Diamonds is fluorescence as for many years it has been seen as a bad thing and something to avoid.

But in reality, only a small number of Diamonds with very strong fluorescence impact on the look of the stone as it can give them a slightly milky appearance but this doesn’t happen with every Diamond that has very strong fluorescence (I’ve seen some stunning stones with very strong fluorescence).

And you will pay more for a Diamond with no fluorescence, assuming that all other factors are the same.

So don’t be put off by a Diamond that has little, medium or strong fluorescence as it won’t impact how the stone looks and can actually make your stone pop a little in strong sunlight!

Reports (Certificates)

GIA Lab Report

Most Diamonds for sale now come with reports but not all reports are the same.

Just to clear things up, Diamonds reports are often sold as certificates or certified Diamonds but they aren’t actually certificates, they are reports as there are differences between these two types of document.

The most popular gem lab for Diamond reports are the GIA (Gemological Insitute of America) as they are one of the leading authorities on Diamonds.

But there are other gem labs, such as IGI and HRD, that are also reputable gem labs and Diamonds with reports from these labs shouldn’t be ignored.

However, there are times when the documentation with a Diamond should cause you to run away and that is if the document says something like “Diamond Certificate” or “Certificate of Authenticity” as no reputable gem lab includes this wording on their documents.

Oval Cut Price

Prices for Oval Cuts are usually slightly lower per carat than the equivalent Round Brilliant Cut, this is very much due to this style of cut being consistently very popular as Ovals rarely go out of fashion as it is very much a timeless style.

If you want to see the latest Oval Cut prices, then check out our Diamond Price guide, which I update every month.

Conclusion

I’ve covered everything you need to know in order to buy the right Oval Cut Diamond for you and this is the same whether you are buying and Natural or Lab-grown Diamond.

To summarize again, for the majority of buyers I would recommend buying a:

  • F, G or H color
  • VS1 – SI1 Clarity
  • A stone with a subtle or very faint bow tie
  • Excellent or Very Good Symmetry and Polish
  • A report from a reputable gem lab

If you have a very large budget or want the ultimate show-off Diamond, then go for a D Flawless or as close as you can get.

I'm Paul Haywood FGA DGA, the owner and founder of Haywoods Gems, I'm a fully qualified Gemmologist and Diamond Grader from the Gemmological Association of Great Britain.

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