Oval Cut Diamond Guide

Last updated on December 16, 2021

Oval is one of the most brilliant diamond cuts available on the market. It makes fingers look elongated and appears larger than its actual carat weight. If you are interested in buying a diamond with an elegant rounded design, this oval cut diamond guide is a must-read.

History of Oval Cut Diamonds

The oval cut belongs to the family of fancy shapes and has a long history, undergoing many changes since its early years. The earliest oval cut diamonds date back to the 1300s; however, they have never been described as oval in literature until the 1800s.

The modern oval brilliant cut was created by a Russian-born diamond cutter Lazare Kaplan in 1957. Before inventing the modern oval cut, Kaplan was mastering his skills in cleaving, a process in which cracked or heavily included diamonds are cut into smaller, less included stones. In other words, he was working with diamonds that other cutters considered “worthless”, turning them into gorgeous stones. However, his talent was not fully recognized until he designed the modern oval cut, significantly improving its brilliance.

The modern oval cut is a modified version of the round brilliant cut. It has 57 or 58 facets and features an elongated shape giving a gemstone an illusion of higher carat weight. This is one of the reasons the cut has always been a popular choice among jewellery lovers around the world.

Oval Cut Diamond Cut Quality

The quality of the cut is the most important factor in maximising the brilliance and fire, meaning it greatly affects the appearance of a diamond.

While the Gemological Institute of America (GIA) and other lab entities provide cut grading for the round brilliant cut, they do not give a cut quality grade for fancy shaped diamonds, including the oval cut. This is because fancy shapes have many non-standardised facet structures, meaning they can be cut to a wide range of proportions. However, grading laboratories list information on polish and symmetry, which are some of the key factors to choosing a brilliant and sparkly stone.

When choosing an oval cut diamond, make sure to pay attention to the facets of the stone and their symmetry. The facets on the right and left halves should have the same shape. All the points of the facets should meet, and there should not be missing or extra ones. Symmetry is the key to maintaining the overall beauty of the stone.

Due to their elongated shape, most oval cut diamonds exhibit a bowtie effect, which occurs when some of the entering light leaks out from the centre of the stone and does not bounce back to the table. Sometimes the effect is easily noticeable, and other times it is hardly visible. The thing is that a prominent bowtie effect distracts from the beauty of the stone, which is why you should make sure the diamond you choose does not have a dominant bowtie, meaning it is not the first thing you notice when looking at an oval cut diamond.

Since there is no industry-wide consent on what cut parameters make an ideal oval cut diamond, it is recommended to use the table below as a general guideline for evaluating the cut quality of oval cut diamonds.

Oval Cut Diamond Colour

The colour of oval cut diamonds is graded on a scale from D to Z, where D signifies a completely colourless stone and Z means an easily noticeable yellow or brown tint.

As a general rule, smaller oval cut diamonds, those weighing 0.50 carats and less, hide colour better than larger ones. That is why, depending on the size of the diamond you are going to purchase, you may not need to buy a premium colourless stone, even if you want it to look white. While it is usually impossible to see the difference between two adjacent colour grades for an untrained eye, the price difference can be significant.

In general, it is recommended to opt for H colour or better to have a diamond that will appear white and colourless to the naked eye. However, keep in mind that colour should be compared on a case-by-case basis.

The chart below provides a general guideline for evaluating colour in the oval cut diamonds.

Oval Cut Diamond Clarity

The GIA grades clarity of oval cut diamonds on a scale from FL to I3, where FL means a flawless stone and I3 indicates a heavily included diamond.

Due to their facet arrangement and excellent light performance, oval cut diamonds hide inclusions and blemishes fairly well. Moreover, smaller oval cut diamonds hide imperfections better than larger ones do, which is why if you are going to purchase a smaller stone, you may opt for a lower clarity grade such as SI1 and SI2 while keeping an eye-clean appearance.

The chart below provides a general guideline for evaluating clarity in oval cut diamonds.

Oval Cut Diamond Length to Width Ratio

The length to width ratio expresses how relatively long or wide a diamond appears. It is calculated by dividing the length of the diamond by its width. For example, if the length of an oval cut diamond is 10.5mm and the width is 8mm, its length to width ratio is 1.3.

Each fancy diamond shape has a certain length to width ratio that is considered most appealing for that shape. While personal preference prevails, the optimal ratio for oval cut diamonds is between 1.35 – 1.50. The higher the ratio, the thinner an oval diamond looks.

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