Oval Cut Sapphire: Pros, Cons & Fire

The oval stretches the brilliant plan along one axis. Our model is 1.331 to 1, with 93 facets, 64.0% deep and a 40.99° pavilion figure. It is the shape sapphire is most often sold in.

Against the T73 in sapphire it wins clearly on fire and a little on sparkle, and gives up nearly a third of the light. Against the same oval in diamond it holds far less light when tilted.

Sapphire is dichroic: viewed along one direction in the crystal a blue looks purer, across it greener. In a long oval, how the cutter lays the length against that direction shows face-up.

Is an oval a good cut for sapphire? Pros and cons

Pros

The most fire we measure in sapphire 74 vs 37
A little more sparkle than the T73 87 vs 80

Cons

Darkens quickly when tipped 58 vs 92
Less light than the T73 66 vs 94
A quarter of the light leaks 26 vs 5
Heavier than a diamond oval 1.62 vs 1.42 ct

Compared with the T73 Round Brilliant in sapphire and with the Oval Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 2 (Spread) or 5% (weight); Tilt counts as a pro only for a stone within 5 points of the brilliance it is compared with. How we measure.

All eight scores against the T73

At a glance: the Oval Cut in sapphire (white) against the T73 Round Brilliant in sapphire (dashed): solid white where it reaches further, hatched where it falls short. Each pro and con is explained, with pictures, below.

Against the T73 Round Brilliant in sapphire: ahead on 2, behind on 6.

Global73, the comparison 79, difference −6
Brilliance66, the comparison 94, difference −28
Fire74, the comparison 37, difference +37
Scintillation87, the comparison 80, difference +7
Spread99, the comparison 100, difference −1
Symmetry98, the comparison 100, difference −2
Shape-norm77, the comparison 102, difference −25
Tilt58, the comparison 75, difference −17

Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring.

Open it in the Cut Performance Wheel

What a sapphire gains as an oval

The most fire we measure in sapphire

Fire 74 against 37 for the T73 Round Brilliant in sapphire: 37 points higher

Fire 74, twice the T73's 37. The dispersion is the same corundum figure in both; the elongated plan changes how the returned light is spread into colour. The diamond oval still scores higher, 92.

Oval cut in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 74) — Look at the coloured flashes: those are fire. Same light, same size, same face-up angle; rendered by our 3D Gemstone Simulator from each cut's own model.

T73 round brilliant in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 37) — Look at the coloured flashes: those are fire. Same light, same size, same face-up angle; rendered by our 3D Gemstone Simulator from each cut's own model.

Try it yourself: See the fire in the 3D Gemstone Simulator

A little more sparkle than the T73

Scintillation 87 against 80 for the T73 Round Brilliant in sapphire: 7 points higher

93 facets stretched along the length, against the T73's 73.

Oval Cut · 93 facets · Scintillation 87

T73 Round Brilliant · 73 facets · Scintillation 80

Scintillation follows the number of facets: more facets, more and smaller flashes as the stone moves. Count the facets in each crown. Drawn from each cut's own model.

Try it yourself: Compare the Scintillation spoke in the Cut Performance Wheel

The catch with an oval sapphire

Darkens quickly when tipped

Tilt 58 against 92 for the Oval Cut in diamond: 34 points lower

At 20° it keeps 58 of its face-up light; the diamond oval keeps 92. That is the oval's largest gap against diamond on any score.

Oval cut in sapphire tilted 0 degrees: Light Return map, 22% of the face leaking — Tilt is how much of its own face-up light a stone keeps when tilted. Each frame is the Light Return map with the stone tilted away from you by the angle shown; grey is light leaving through the pavilion. The share under each frame is that picture's own.

Oval cut in sapphire tilted 10 degrees: Light Return map, 29% of the face leaking — Tilt is how much of its own face-up light a stone keeps when tilted. Each frame is the Light Return map with the stone tilted away from you by the angle shown; grey is light leaving through the pavilion. The share under each frame is that picture's own.

What helps: No elongated cut we measure holds much better in sapphire. The Square Cut Sapphire keeps 84 when tipped, at 78 brilliance.

Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel

Less light than the T73

Brilliance 66 against 94 for the T73 Round Brilliant in sapphire: 28 points lower

Brilliance 66 against 94. The same oval in diamond returns less still, 47: the shape costs light in both stones.

Oval cut in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 66) — Red, green and blue = light returning to the eye; grey = light leaving through the pavilion. This is the head-on view; the Brilliance score averages a wider cone of light, so the score can differ from what one picture shows.

T73 round brilliant in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 94) — Red, green and blue = light returning to the eye; grey = light leaving through the pavilion. This is the head-on view; the Brilliance score averages a wider cone of light, so the score can differ from what one picture shows.

What helps: For light in sapphire, a round: DG-M5 Sapphire returns 100. Among elongated shapes the oval already leads; the Pear Cut Sapphire returns 62 and the Marquise Cut Sapphire 55.

Try it yourself: Open this Light Return map in the simulator

A quarter of the light leaks

Leakage 26 against 5 for the T73 Round Brilliant in sapphire: 21 points higher

About a quarter, 26%, escapes through the back in our census, where the T73 lets 5% go. The pavilion figure, 40.99°, is above sapphire's 36.4° guide minimum, so the leak is not a too-shallow pavilion.

What helps: Not by steepening, at 40.99°. The Teardrop Cut Sapphire leaks 23%, a little less; a round such as the T73 Round Brilliant Sapphire leaks 5%.

Try it yourself: Tilt it yourself in the simulator's light map

Heavier than a diamond oval

1.62 ct at 6.5 mm, against 1.42 ct for the same cut in diamond (+14%)

A 6.5 mm wide oval weighs 1.62 ct in sapphire and 1.42 ct in diamond.

A Oval Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Size it by length and width; the oval's face-up area is what shows.

Try it yourself: Weights in all seven gemstones on the Oval Cut page

Who an oval sapphire suits

Choose the oval for a sapphire where colour flashes and a long outline matter, in a ring seen face-up rather than a stone that swings. In a pale or colourless sapphire, the fire figure is the oval's strongest argument.

For the most light, DG-M5 Sapphire. For a softer drop with nearly as much fire, the Teardrop Cut Sapphire at 64.

Oval Cut Sapphire: questions

Is an oval cut good for sapphire?

It is our top sapphire cut for fire, 74 where the T73 manages 37, and a weaker one for light, 66 where the T73 returns 94.

Does an oval sapphire have a bow-tie?

Ovals can show a darker band across the middle. We have no bow-tie metric, so we cannot score it here.

What does a 6.5 mm wide oval sapphire weigh?

1.62 ct for our 1.331 to 1 model, against 1.42 ct in diamond.

Oval or round for a sapphire ring?

Round for light, oval for fire: DG-M5 returns 100 against 66 here, and the oval scores 74 for fire against 39.

Get the Oval Cut files

6 formatsMillimetresWatertight

Oval Cut 3D files

The Oval Cut as exact geometry: 97 planar facets, real-world scale, ready for CAD, rendering, printing and casting.

STEPExact faceted solid for CAD
3DMRhino, closed mesh on its own layer
STLWatertight mesh for printing and casting
OBJMesh for modelling and rendering
FBXBlender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
GLBWeb, AR and quick previews

€9.99 · Personal useBuy the 3D files

GemCad96 index

Oval Cut cutting files

The Oval Cut as a faceting design: 73 + 20 girdles = 93 facets, 96 index, 2-fold mirror-image symmetry, ready for the machine.

.ascGemCad design file, 96 index gear
.csvTier table: angles, indices and cutting order
DiagramPrintable faceting diagram

€9.99 · Personal useBuy the cutting files

Questions before you buy? Email us.

More gemstones and cuts

Sapphire: optical properties and the top ten cuts · The Oval Cut: specifications, model and files

Oval Cut Sapphire: twice the round's fire, the most we measure