Oval Cut Diamond: A Buying Guide

Oval cut diamond.

The ever flattering oval shape is symmetrical and exhibits a similar fire and brilliance to round shaped diamonds. A scintillating twist on the classic round brilliant, the elongated shape can create the illusion of larger size. Oval diamonds are highly versatile, remarkably elegant, and distinctive.

Oval Cut Diamond

Oval cut diamond.

Created by Lazare Kaplan in the 1960's, oval diamonds are a modified brilliant cut (like virtually all round cuts). Because the two shapes possess a similar fire and brilliance, the oval is an ideal choice for a customer who likes the look of a round diamond, but wants something more unique. The slender shape can also make the finger of the wearer appear longer and slimmer, an effect often desired.

Oval Cut Diamond Buying Guide


Oval Cut Diamond Quick Guide

Unique Features
Symmetrical, elongated rounded shape
Usually 58
L/W Ratio
Typically 1.33 - 1.66
19th Century
Expert Tip
Optimises carat weight and elongates finger

Oval Cut Diamond Ring

Oval Cut Diamond Ring

Oval cut diamond ring.

Oval Cut Diamond Features

Oval Cut Diamond Features

Oval cut diamond features.

The oval cut is a rounded shape typically comprised of 58 facets with a typical ratio between 1.33 and 1.66.

Somewhere in between the round brilliant and the pear shape, the oval cut is the perfect choice if you are wishing to savour the sparkle of the round brilliant in a slightly rarer and more elongated form.

A "bow-tie effect" occurs when light passing through the diamond casts a shadow across the central facets of the diamond. This shadow can be reduced by altering the depth of the pavilion, and adjusting the angles of the table and facets to better diffuse light in the central area. This effect also occurs in the pear, marquise and heart shapes.

Oval Cut Diamond Bow-tie

Oval cut diamond bow-tie.

Due to their elongated shape, most oval cut diamonds exhibit bow-tie effect, which occurs when some of the light at the centre is leaked and not reflected back to the table.

Sometimes the bow-tie effect in oval diamonds is easily noticeable and other times it is hardly visible. The truth is that a prominent bow-tie effect distracts from the beauty of the diamond, which is why you should make sure the diamond you choose doesn't have a dominant bow-tie, meaning it's not the first thing you see when looking at an oval cut diamond.

Some oval diamonds may have slight bow-ties that do not significantly affect their radiance and scintillation, and may even add to their unique appeal. However, you should definitely avoid buying an oval diamond where the bow-tie effect causes large dark areas. Trust your eyes when you examine an oval diamond in order to bypass the risk of buying a diamond with an obvious bow-tie.

Bow-ties are often a result of the diamond pavilion being cut too deep, similar to a "nail head round diamond".

Oval Cut Diamond Expert Guide

Ratio is an important aspect to consider with the oval shape as it can have a significant impact on both the light dispersion within the diamond and the appearance of the finger. When selecting an oval shape it is important to reconcile the relative benefits of the longer shape (larger ratio) and the more rounded shape (smaller ratio). The former will better elongate the finger, while a more rounded shape will better prevent the bow-tie effect.

Preferences vary on how narrow or fat an oval cut diamond should be, so choose what appeals to you personally (though a length to width ratio of 1.35 - 1.50 is considered the classic oval cut). A slightly thinner cut may look most appealing in a setting where the diamond is flanked by side stones.

Oval Cut Diamond - Cut Guide

The quality of the cut is the most crucial factor in maximizing the brilliance and fire of the diamond.

While the GIA provides cut grading for some cuts, such as the round brilliant, it doesn't provide cut grading for oval cut diamonds due to their complex and unique structure.

The chart below serves as a general guideline for evaluating the cut of an oval diamond:

Swipe left to see more.

Oval Cut Diamond Excellent Very Good Good Fair Poor

Depth refers to the distance between the culet and the table when a diamond is viewed from the side.

The depth % of a diamond is calculated by dividing the depth of the diamond by the width of the diamond. So, if a diamond is 3 mm in depth, and 4.5 mm in width, its depth % is 66.7.

The lower the depth %, the larger a diamond of a given carat weight will appear when viewed from above (since more of the diamond's size is in its width vs. in its depth).

Depth % is incorporated in the cut grade of a diamond. For this reason, when purchasing a diamond, use the cut grade first (since it balances multiple measurements, not just depth %). Once two diamonds of equal cut are being compared, consider depth % as a further refinement.

Learn more about the anatomy of a diamond.

58 - 62 56 - 57.9 or 62.1 - 66 53 - 55.9 or 66.1 - 71 50 - 52.9 or 71.1 - 74 <50 or >74

The table is the uppermost, flat surface of a diamond, which runs parallel to the plane of the girdle.

The table % of a diamond is calculated by dividing the width of the table facet by the width of the diamond. So, if the table facet is 3 mm across, and the diamond is 4.5 mm wide, its table % is 66.7.

Table % is incorporated in the cut grade of a diamond. For this reason, when purchasing a diamond, use the cut grade first (since it balances multiple measurements, not just table %). Once two diamonds of equal cut are being compared, consider table % as a further refinement.

Learn more about the anatomy of a diamond.

53 - 63 52 or 64 - 65 51 or 64 - 65 50 or 69 - 70 <50 or >70

A diamond's symmetry is the arrangement, size, and shaping of diamond's facets. The facets are the flat planes that run along the surfaces of the diamond. Symmetry is angles and lines that form the placement of the facets. Nowadays, symmetry is completely controlled by the manufacturing process. Machines very carefully cut diamonds to produce the most accurate shapes. However, at times the diamond cutter will leave a symmetry imperfection in the diamond in order to prevent a different inclusion from showing in the finished diamond. Symmetry is a subset of the diamond's cut grade.

Learn more about diamond symmetry.

Good to excellent Good to excellent Good to excellent Fair to Excellent Poor to Excellent

The term "polish" refers to the overall condition of the surfaces of a finished diamond. A rating is assigned based on the amount of polishing lines that are visible. These polishing lines are caused by very small diamond crystals which are embedded in the polishing wheels used by diamond cutters to polish the surface of the diamond after cutting. Diamond polish is important because it can affect the degree to which light is able to pass through a diamond, rendering it more or less brilliant. Diamonds that are laboratory certified with a good, very good, or excellent polish rating are the most desirable. Diamonds that have poor polish will be less brilliant and not as desirable or valuable. Reputable jewellers diamonds are graded after examining the diamond facet by facet.

Learn more about diamond polish.

Good to excellent Good to excellent Good to excellent Fair to Excellent Poor to Excellent

The girdle is the outer edge of the diamond, where the crown (top) meets the pavilion (bottom).

A girdle may be faceted (a series of tiny polished sides going around the diamond), bruted (a single continuous unpolished surface going round the diamond; no longer common), or polished (a bruted girdle that has been polished smooth). Whether a girdle is faceted, bruted, or polished usually has no impact on the appearance or value of the diamond.

The girdle is described according to its width. Often, the width of the girdle varies at different points around the diamond, and is quoted in a range designating the thinnest and thickest point along the girdle (e.g. "Thin - Medium" means the diamond's girdle varies in width from thin at the narrowest point to medium at the widest point).

Learn more about the anatomy of a diamond.

Very Thin - Slightly Thick Very Thin - Slightly Thick Very Thin - Thick Very Thin - Very Thick Ex. Thin - Ex. Thick

The culet (pronounced cue-let) is the small area at the bottom of a diamond's pavilion. The culet can be a point or a very small facet sitting parallel to the table.

The culet size as determined by the GIA, is shown using the following scale:

None, Very Small, Small, Medium, Slightly Large, Large, Very Large.

Any culet size of Medium or smaller will be invisible to the naked eye, and have no negative impact on a diamond's appearance. However, if a culet is Slightly Large or larger, it may allow light entering from the crown to pass straight through the culet facet, reducing the diamond's brilliance. This may also make the culet appear as an inclusion, or create a dead area on the diamond where the light is escaping through the bottom.

Learn more about the anatomy of a diamond.

None Very Small Small Medium > Medium

The length to width (L/W) ratio is calculated by dividing a diamond's length (the longer measure) by its width (the shorter measure that runs perpendicular to length).

For example, an Oval Cut diamond that is 5.00 mm in length and 3.3 mm in width will have a L/W ratio of 1.50 (5.00/3.33). A perfectly round or square diamond will have a length to width ratio of 1.00, but many will be off slightly since they are often not perfectly cut. Any L/W ratio of 1.05 or less will appear perfectly round or square to the naked eye.

L/W ratio is more commonly used in fancy shapes. There is no "ideal" L/W ratio in a fancy shape diamond. What is important is what looks pleasing to you.

1.35 - 1.50 1.30 - 1.34 or 1.52 - 1.55 1.25 - 1.29 or 1.56 - 1.60 1.20 - 1.24 or 1.61 - 1.65 <1.20 or >1.65

Oval diamond cut guide.

Oval Cut Diamond Ratio

Oval cut diamond length to width ratio.

Oval Cut Diamond - Color Guide

Evaluating color in oval diamonds is subjective. Keep in mind that many buyers may actually prefer the ever so slightly warmer colors of a G-H diamond over the cool colorlessness of a D-F diamond. In fact, most of the premium in price associated with oval diamonds at the higher end of the color scale is driven by supply and demand; customers want the D-F color grades, and are willing to pay a premium to get them. In a world without diamond color grading, the price premium for higher grades would be much lower, as the actual differences in color are difficult to perceive.

Color in oval cut diamonds is graded by the GIA on a scale from D to Z.

As a general rule, smaller oval diamonds hide color better than larger ones do. That is why. depending on the size of the diamond you are going to purchase you may not need to buy a premium colorless diamond even if you want it to look colorless. While its usually impossible to see the difference between two color grades for an untrained eye, the difference in price can be significant. The color chart below provides a general guide for evaluating color in oval diamonds:

Swipe left to see more.

Oval Cut Diamond Excellent Very Good Good Fair Poor
< .50 ct. D - G H - I J - K L - M > M
.51-1.0 ct. D - F G H - I J - K > K
1.0-2.0 ct. D - F D - F G - H I - J > J
>>2.0 ct. D - F D - F G H - I > I

Fluorescence refers to a diamond's tendency to emit a soft colored glow when subjected to ultraviolet light. Roughly 30% of diamonds fluoresce to some degree.

Colorless (D-F) fluorescent diamonds sell at up to a 15% discount since the fluorescence is perceived as a defect, even though the visible effects of Faint to Medium fluorescence are perceptible only to a gemologist using a special UV light source.

Because the fluorescent glow is usually blue (which is the complementary color to yellow) fluorescence can make diamonds of I-M color appear up to one grade whiter. For this reason, I-M diamonds tend to sell at a slight premium when they possess Medium to Very Strong fluorescence.

Exercise caution in purchasing a diamond with Strong fluorescence in D-F color diamonds or Very Strong fluorescence in G-H color diamonds (which do not possess enough body color to offset the higher degree of fluorescence).

Learn more about diamond fluorescence.

None Faint - Med Strong Very Strong Very Strong

Oval diamond color guide.

Swipe left to see more.

Oval Cut Diamond Color

Oval cut diamond color.

Oval Cut Diamond - Clarity Guide

Like color, evaluating clarity in oval diamonds is subjective. GIA provides excellent help with their clarity grades. Still, it is important to understand that each customer will have a unique standard for clarity. Some may be perfectly comfortable with an inclusion as long as they cannot easily see it. Others may insist on a more technically flawless appearance.

Due to their shape, oval diamonds tend to hide blemishes and inclusions well. It is nearly impossible to notice imperfections near the rounded end or where the setting will lay.

While clarity in oval cut diamonds is graded by the GIA on a scale from FL to I3, it is important to understand that everyone has a unique standard for clarity. Some may feel comfortable with inclusions as long as they are not eye seen, while others insist on flawless appearance. The clarity chart below provides a general guide for evaluating clarity in oval diamonds:

Swipe left to see more.

Oval Cut Diamond Excellent Very Good Good Fair Poor
< .50 ct. FL - VS2 SI1 - SI2 I1 I2 > I2
.51-1.0 ct. FL - VS1 VS2 - SI1 SI2 I1 - I2 > I2
1.0-2.0 ct. FL - VVS2 VS1 - VS2 SI1 - SI2 I1 > I1
> 2.0 ct. FL - VVS2 VS1 - VS2 SI1 SI2 > SI2

Oval diamond clarity guide.

Swipe left to see more.

>Oval Cut Diamond Clarity

Oval cut diamond clarity.

Oval Cut Diamond History & Background

Although oval shaped diamonds were first introduced over 200 years ago, the modern oval cut was invented in the early 1960s by leading Russian cutter Lazare Kaplan. The cut eventually earned him a place in the Jewellers International Hall of Fame, however, Kaplan also left his mark on the diamond industry with his unique ability to split a rough diamond into smaller stones with a single blow. This process is known as cleaving.

When a rough material is poorly shaped or contains defective flaws that prevent it from being turned into a single stone, it must be split along the grain. Kaplan became famous for his expertise in taking stones that were otherwise deemed unworthy and transforming them into beautifully cut diamonds.

Oval Cut Diamond History

Oval cut diamond history.

Learn more about what you need to know in our ultimate buying guide, if you're thinking of buying a oval cut diamond. We break it all down from pricing, other shapes comparison and engagement ring setting choices.