Oval Shape Gemstones

What an Oval Cut Is

An oval is an elliptical modified brilliant — a stone whose outline is a smooth closed curve with no corners, faceted on the same principles as a round brilliant but stretched along one axis.

The facet arrangement descends directly from the round: a table, a crown of bezel, star and upper girdle facets, then a pavilion of main facets and lower girdle halves meeting at a culet or, in coloured stone, a short keel. A standard oval carries fifty-six or fifty-eight facets, the round brilliant's complement redistributed around an ellipse. The word modified is doing exact work. An oval is not a separate cutting family in the way a step cut is, where rectangular facets run in tiers parallel to the girdle. It is the round brilliant's geometry adapted to a longer outline, and everything good and bad about it follows from that adaptation.

The modern oval brilliant is credited to Lazare Kaplan, who refined and popularised it in 1957. What he established were facet angles and proportions that made an elongated brilliant behave optically like a round one rather than a compromised one. Our oval collection is the largest single shape holding we keep, which reflects demand rather than any accident of supply.

Why an Oval Looks Larger

An oval of a given carat weight generally presents a larger face than a round of the same weight. This is true, it has a straightforward explanation, and it is also routinely overstated.

Much of a brilliant's volume sits in the pavilion, below the girdle, invisible once the stone is set. What the eye registers is face-up spread — the outline seen looking down at the stone, measured in millimetres. Elongating that outline increases its area relative to the volume beneath it, because the ellipse gains length faster than the pavilion gains depth. Against a round of equal weight, a well-proportioned oval typically shows something near ten per cent more face-up area, and the elongation exaggerates the impression further, because a long shape reads as bigger on a finger than a compact one of identical area.

The honest qualification is that this holds only when the oval is well cut. A badly proportioned oval can be very deep, usually to retain weight from the rough, and a deep oval spreads no better than a round, sometimes worse.

So compare millimetre dimensions, never carats. Two two-carat ovals can differ by more than a millimetre in length, and the carat weight tells you nothing about which is which. The same discipline applies against a round.

Length-to-Width Ratio

The length-to-width ratio is the stone's length divided by its width, and it is the most useful number on this page. A stone measuring 9.00 by 7.00 millimetres has a ratio of 1.29. One measuring 10.50 by 7.00 has a ratio of 1.50. Both are ovals; they do not look remotely alike.

Most buyers settle between roughly 1.30 and 1.50, and that range is where the shape is generally held to be at its best — long enough to read clearly as an oval, compact enough to hold light evenly across the middle. Within the band the choice is personal.

At 1.20 the outline is close to round. It reads as full and generous and sits well on a small hand, but it can look heavy, and it spreads less than a longer stone of the same weight, forfeiting part of the reason for choosing an oval at all.

At 1.60 the stone is markedly elongated and elegant, closer in feeling to a marquise than to a round. The costs are real: very long ovals can look fragile even when they are not, they are harder to match in a pair, and they are more prone to the bow-tie described below, because the pavilion facets towards the ends must be steeper.

There is no correct ratio, and anyone who tells you there is one is describing their inventory rather than advising you. What must not happen is that the ratio goes unchecked. It is not encoded in the carat weight, and it is easily misjudged from a photograph that has been cropped or scaled. Take the two measurements and divide.

The Bow-Tie

The bow-tie is the defect specific to elongated brilliants.

It appears as a dark band across the width of the stone at its centre, pinched in the middle and spreading towards the long sides — the shape a bow-tie makes. The cause is not a flaw in the material. It is the wearer. In an elongated brilliant the pavilion facets across the central portion collect light from a fairly narrow band of directions, and in normal viewing the observer's own head and shoulders sit precisely in that band. The facets have nothing to return, so they go dark. The longer the stone and the steeper the pavilion, the wider the obstruction and the more pronounced the effect.

Almost every oval has some bow-tie. So does almost every pear, marquise and elongated cushion — it is a property of the geometry, not a failure of workmanship, and a stone advertised as having none has usually been photographed rather than examined. The question is never whether one is present but how severe it is: a faint softening that opens and closes as the stone moves, or a black bar that stays put and eats a third of the face. The first arguably adds contrast; the second is a dark stripe you will notice for as long as you own the stone.

It can only be judged in person, or in an honest unedited video with the stone in motion under ordinary light. It does not appear in a retouched photograph. We film stones rather than rely on stills for that reason, and the same argument is set out in our buyer's guide to pear-shaped gemstones, where the problem is more acute still.

Windowing and Extinction

Two other faults are often confused with a bow-tie.

Windowing is a transparent area, usually central, where you see straight through the stone to whatever lies behind it. It occurs when the pavilion is too shallow for the material's refractive index, so light entering the crown passes out of the bottom instead of returning to the eye. A window is a cutting decision made to retain weight from flat rough, and unlike a bow-tie it is a plain fault with nothing to be said for it. Hold the stone over printed text and see whether you can read through the middle.

Extinction is the opposite failure — areas that stay dark however the stone is moved, because the facets there are angled too steeply and light is trapped and absorbed rather than returned. A bow-tie is a localised shadow that shifts and breathes as the stone tilts; extinction is static blackness in fixed zones.

Which Gemstones Suit an Oval

Some material cuts better as an ellipse, and the reasons are worth stating.

The first is orientation. Strongly pleochroic stones show different colours along different crystal directions, and the cutter cannot choose the outline freely: the table must face the best colour, and the rest is negotiated around that. Tanzanite is trichroic, showing blue, violet and burgundy along three axes; kunzite and iolite are similarly constrained. When the best colour direction runs along the crystal's length, as it does in the flat elongated rough these species yield, an ellipse keeps the colour and loses the least weight. Much of the finest tanzanite is oval for that reason.

The second is durability. An oval has no corners, and corners are where brittle stones chip. Emerald is brittle because its internal fractures are planes of weakness; opal is soft and intolerant of knocks. A cut with four sharp points concentrates every impact at those points, which is why the emerald cut evolved its cropped corners. An oval removes corners altogether, which for fragile material is a real advantage.

The third is colour depth. Pale material builds colour along the path light travels through it, and a brilliant-cut oval of good depth gives light a longer journey than a shallow stone of the same face-up size. This is why morganite and aquamarine are so often cut as generous ovals: a pale beryl cut flat to maximise spread reads washed out however large it is.

The fourth is simply the shape of the rough. Water-worn pebbles, elongated crystals and flattened seams all yield more finished weight as an ellipse than as a round, which is why ovals are common across sapphire and ruby.

Setting an Oval

The oval's practical advantage over most fancy shapes is that it has nothing vulnerable to protect. A pear has a point, a marquise has two, an emerald cut has corners that must be shielded. An oval is a continuous curve, and a jeweller setting one is never working around a weak spot.

The choice between four claws and six is the main decision. Four leave more of the stone visible and give a cleaner line, and they are sound on a compact oval nearer 1.30. Six suit an elongated outline better, because the extra claws sit along the long sides where an unsupported span would otherwise flex under pressure, and because six points of contact hold the stone's axis true if one claw is knocked.

Wherever the claws sit, the ends are the point of contact that matters. They are the part that meets a doorframe first, so at least one claw should engage each end rather than gripping the sides alone. A bezel does this comprehensively and is safest for brittle material, at the cost of hiding a rim of the stone.

Orientation is a design decision with no technical answer. North-south — the length running along the finger — is traditional and lengthens the hand. East-west, set across the finger, reads wider and sits flatter against adjacent bands. It is worth settling before commissioning a setting rather than after.

Judging an Oval Before You Buy

Start with the millimetre dimensions, which should be stated for every stone. Divide length by width and satisfy yourself about the ratio. Then consider depth: if the face-up dimensions seem small for the weight, the weight is in the pavilion, and you are paying for material nobody will ever see.

Watch the stone moving under ordinary light and judge the bow-tie for severity, not presence. Check for a window by looking for anything visible through the centre, and for extinction by noting whether dark zones stay dark as the stone tilts.

Then examine symmetry, which is where cheap ovals give themselves away. The two ends should be identical in curvature and equally rounded; one blunter than the other is a fault that is impossible to unsee once noticed. Look also at whether the outline is a true continuous ellipse or slightly shouldered — flattened where the curve should be steadily turning, which happens when a cutter is chasing weight.

The standard we apply to all of this is set out in how SARATTI grades gemstones.

Choosing an Oval

An oval is the shape to choose when you want the light behaviour of a round brilliant with more presence for the weight, and when you would rather not manage the vulnerable points and corners other fancy shapes bring. It suits nearly every species, it flatters nearly every hand, and it forgives setting decisions that would trouble a pear.

What it asks in return is that you check two things nobody puts in a headline: the ratio, and the bow-tie. Neither is visible in a carat weight, and neither can be recovered afterwards.

Every stone here is listed individually, with its own measurements, so the ratio can be worked out before you commit to anything. Only part of what we can reach is listed online, and if what you want is not listed — a particular ratio, a particular length, a species we do not currently show in this shape — describe it, and we will go and look.