The Ultimate Oval Cut Diamond Guide

Beautiful Oval Cut Diamond Ring from Jean Dousset

Why More People Want Oval Cut Diamonds

Customers are asking for Oval cut diamonds more than ever before. Here are some of the reasons we think oval cut diamonds make a great engagement ring:

  • They are femine and romantic in shape.
  • They have brilliant sparkle similar to a round brilliant diamond, but with the added allure of an elongated shape.
  • They enhance your ring finger.
  • Ovals are more unique so your ring will stand out from the crowd.

Three Advantages of Oval Cut Diamonds

1. Oval shaped diamonds enhance your finger.

An oval diamond can accentuate long fingers and give the illusion of length to shorter fingers. Works for all fingers!

2. Ovals are less expensive than round diamonds.

The price per carat savings can be anywhere from 10 - 20%. So you can put some cash in your pocket, or get a larger diamond!

3. Ovals look larger than round diamonds.

The elongated shape will have a larger look than a round diamond of the same carat weight. For example, the average diameter of a well cut 1ct round diamond will be about 6.4 x 6.4mm. A well cut oval diamond should measure close to 7.75 x 5.50mm. Carat for carat, the oval cut diamond will look larger than the round brilliant diamond. So not only is the oval 10-20% less in cost, it also looks larger!

History of Oval Cut Diamonds

When did the oval cut come on the jewelry scene?

Oval cut diamonds have been around for centuries. One of the most famous of all oval diamonds is the Koh-I-Noor (Persian for Mountain of Light) diamond, which dates back to the early 1300s. This 186 carat gem was first set as the eye of a sacred Indian Hindu goddess statue. But then it was stolen by the Turks in 1310. After the British conquest of the Punjab in 1840, the diamond ended up in the possession of Queen Victoria. The crudely cut stone was rather lifeless and irregular in shape. To improve it's appearance, she had it cut down to 105.6 carat oval brilliant. Today this diamond is set in the front of the Queen Mother's Crown, part of the Crown Jewels of the United Kingdom located in the Tower of London.

These early oval diamonds were very rudimentary, poorly cut and lacked brilliance. Diamond cutters just didn't have the tools and mathematical skills that their modern counterparts have.

Koh-I-Noor Diamond - one of the worlds first oval cut diamonds Koh-I-Noor Diamond set into Queen MOther's Crown

Koh-I-Noor Diamond loose and set into Queen Mother's Crown

Oval cuts in our modern time.

The modern oval cut was created by Lazare Kaplan, the famous Russian born American master diamond cutter. Lazare Kaplan came from a family of legendary diamond cutters. His cousin Marcel Tolkowsky developed the worlds first round brilliant "ideal" cut, which was called the Tolkowsky Ideal Cut. Kaplan began modifying his cousin's ever popular round brilliant ideal cut into an oval shape. In 1957 Kaplan created the Oval Elegance - and the modern oval cut diamond was born! It was a very significant development in the world of diamond cutting. His modern oval cut diamond had between 56 and 58 facets and was a brilliant cut that could rival the round brilliant. It became the basis for all oval cut diamonds today. Mr. Kaplan was inducted into a Jewelers International Hall of Fame.

How To Choose The Best Oval Cut Diamond?

What length-to-width ratio is best for an oval cut diamond?

A well-proportioned oval cut should have a length-to-width ratio of between 1.25-1.50. Any cut below a ratio of 1.25 starts to look too round. Any cut over a ratio of 1.50 starts to look very narrow, like a marquise cut. In my opinion, I prefer a ratio of about 1.40 to 1.

The diagram below shows you how different length-to-width ratios affect the shapes of oval cut diamonds. But really when it comes down to it, it is your personal preference that dictates the best ratio for the oval cut diamond you purchase.

Oval Cut Diamond Length to Width Ratio

Oval Cut Diamond Length to Width Ratio

What are the best table & depth proportions for oval cuts?

Fancy cut diamonds are not graded by the GIA like round diamonds are. So your GIA diamond grading report (or some call it "certificate"), while ensuring you’re getting a high quality diamond, is not going to tell you what the "cut" grade is. With a round brilliant diamond GIA grades how well the diamond has been cut. It could get one of the following cut grades: Excellent, Very Good, Good, Fair or Poor Cut. On a GIA report for an oval cut diamond it will tell you the diamond's polish and symmetry along with the color, clarity and dimensions. However, if you want your diamond to have maximum brilliance, scintillation and sparkle then it better be cut very well. A well cut diamond will capture the most light and then send that light back out through the top of the diamond. A diamond that is poorly cut will not capture as much light, and/or not return that light through the top of the diamond. So be choosy on your oval cut diamond's cut. That's the secret to making the stone dance on your finger!

Table & Depth Proportions of a Diamond

Table & Depth Proportions of a Diamond

Refer to the diagram of a diamond above to see where a diamond's table, depth, crown height and girdle thickness are measured. The Accredited Gem Appraisers (AGA) published ideal cut specifications for oval brilliant cut diamonds back in the 1980s. The ideal cut specifications for oval cut brilliant diamonds set out by the AGA are:

Table %: 55 - 60%
Total Depth %: 59 - 63%
Length to Width ratio: 1.33 - 1.66: 1
Crown height %: 12 - 15%
Girdle thickness: 0.4 - 4.5%

The key to getting the best oval diamond is to get the opinion of an experienced jeweler trained by GIA. He or she will be able to tell you after a visual inspection if the oval cut diamond you have selected achieves the maximum brilliance for its proportions. Unfortunately, you cannot gauge an oval diamond's cut by simply looking at it's diamond grading report. You need to personally see the diamond while comparing it to another diamond of similar size and quality.

The bowtie effect.

All ‘long’ diamond cuts exhibit some degree of the bowtie effect. Literally, this means you can see two black triangles on their sides, tips attached at the center of the stone in the middle. Hence the name, ‘bowtie’ effect!

Diamond grading labs do not grade the bowtie effect, so whether or not it is distracting to the beauty of the stone is totally dependent on the eye of the beholder. Most people prefer a smaller bowtie effect to a larger one. Once again, that is why you need to physically view the oval cut diamond in person, and compare it to another one, before buying. You cannot do this over the internet.

If the depth of an oval cut diamond is 60% or less, the stone will have a prominent bow tie effect. On the other hand, if the depth is 68% or greater, the bow tie effect will be minimal. But at these depths, an oval cut diamond will lose brilliance and fire. So it will start to look darker and duller than other stones anyway.

Bowtie effect on oval cut diamonds

Notice the two photographs above. The diamond on the left has a very dark (and somewhat ugly) bowtie. It impacts the brilliance of the diamond and puts your eyes focus on the wrong thing. The bowtie on the diamond on the right is very minor and not distracting. Which diamond would you rather have?

Celebrity Oval Cut Diamond Engagement Rings

It's no surprise some of Hollywood's most beautiful women chose an oval cut diamond for their engagement ring. Below are a few celebrity oval cut diamond engagement rings for inspiration.

  • Heidi Klum

  • Blake Lively

  • Salma Hayek

Let's Create The Perfect Oval Cut Diamond Ring For You

Do you have an idea for an oval cut diamond ring? Have you seen a picture of one that you love? Or want to start from scratch and create a one of a kind? Let's talk!

Below are some beautiful oval cut diamond engagement rings we have helped other folks with. Let us know what you think.