Brilliance 66 · Fire 74 · Scintillation 87 · in our census, where the T73 scores 94 · 37 · 80 in ruby
The oval is one of the commonest shapes for ruby, and in our census it is the most colourful: Fire 74, twice the T73's.
Much ruby rough grows as flattened hexagonal crystals, and an oval follows that rough with less waste than a round. Our model stretches the brilliant plan to a length-to-width ratio of 1.331, with 93 facets, a 40.99° pavilion and a depth of 64.0%.
The stretch changes how ruby behaves. Fire doubles against the T73, the light returned falls, and more of it leaks. Against the same oval in diamond, ruby holds far less light when tilted and shows less fire, yet returns more light face-up: Brilliance 66 against 47.
Compared with the T73 Round Brilliant in ruby 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.
At a glance: the Oval Cut in ruby (white) against the T73 Round Brilliant in ruby (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 ruby: ahead on 2, behind on 6.
Fire 74 against 37 for the T73 Round Brilliant in ruby: 37 points higher
The elongated plan sets pavilion facets at many different angles along the stone's length, and each one splits light a little differently. Corundum's dispersion is low, so this is not diamond fire, but it is more colour than any round gives a ruby.
Oval Cut in ruby · Fire 74
T73 Round Brilliant in ruby · Fire 37
Scintillation 87 against 80 for the T73 Round Brilliant in ruby: 7 points higher
93 facets on a longer outline: the scintillation score, which follows the facet plan, edges past the T73's.
Oval Cut · 93 facets · Scintillation 87
T73 Round Brilliant · 73 facets · Scintillation 80
Try it yourself: Compare the Scintillation spoke in the Cut Performance Wheel
Tilt 58 against 92 for the Oval Cut in diamond: 34 points lower
Tipped 20°, the ruby oval keeps 58 of its face-up light; the diamond version keeps 92. No other cut on our ruby pages loses as much against its diamond twin.
Oval Cut in ruby · Tilt 58
Oval Cut in diamond · Tilt 92
What helps: No oval we measure in ruby holds light like a round. If the stone will often be seen at an angle, a round such as DG-Miliano Ruby keeps 83.
Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel
Brilliance 66 against 94 for the T73 Round Brilliant in ruby: 28 points lower
Brilliance 66 against 94. Along its length the pavilion meets light at angles a round never presents, and corundum's 34.6° critical angle lets some of it go. Ovals often show this as a darker band across the middle, the bow-tie, which we do not measure.
Oval Cut in ruby · Brilliance 66
T73 Round Brilliant in ruby · Brilliance 94
What helps: The pavilion already sits at 40.99°, above ruby's 36.4° guide minimum, so steepening it is not the fix our data supports. For more light without a round outline, the Cushion Cut Ruby returns 88.
Try it yourself: Open this Light Return map in the simulator
Leakage 26 against 5 for the T73 Round Brilliant in ruby: 21 points higher
Of the light entering the oval, 26% finds its way out through the pavilion; the T73 in ruby loses 5%.
Oval Cut in ruby · Leakage 26
T73 Round Brilliant in ruby · Leakage 5
What helps: The share does not change with size. The Cushion Cut Ruby leaks 11%.
Try it yourself: Tilt it yourself in the simulator's light map
1.62 ct at 6.5 mm, against 1.42 ct for the same cut in diamond (+14%)
A 6.5 mm wide oval is 1.62 ct in ruby and 1.42 ct in diamond: corundum is about 14% denser.
What helps: Oval settings are made to length and width, so specify the ruby in millimetres.
Try it yourself: Weights in all seven gemstones on the Oval Cut page
Choose the oval for a ruby that should flash colour as well as glow red: it has the most fire of any cut we measure in this stone. It suits a ring seen mostly face-up.
If light matters more than colour flashes, a round gives more: DG-M5 Ruby returns 100. For an elongated outline with a softer point, the Teardrop Cut Ruby keeps most of the fire, 64.
Ruby's two pleochroic colours, purplish red and orangey red, sit at right angles in the crystal, and an elongated outline does not always let the cutter put the better one face-up. That is one reason oval rubies of the same rough can differ in colour.
For colour flashes, yes: Fire 74, the highest we measure in ruby. For returned light, a round ruby beats it, 94 against 66.
Many ovals show a darker band across their width, and in a ruby it reads as a deeper red stripe. Our tools have no bow-tie metric, so the 26% leak figure is the nearest thing we can give.
Diamond has more fire (92 against 74) and holds light far better when tilted; ruby returns more light face-up in this cut (66 against 47).
About 1.62 ct at a length-to-width of 1.331; a diamond of the same size is 1.42 ct.
The Oval Cut as exact geometry: 97 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The Oval Cut as a faceting design: 73 + 20 girdles = 93 facets, 96 index, 2-fold mirror-image symmetry, ready for the machine.
Questions before you buy? Email us.
Ruby: optical properties and the top ten cuts · The Oval Cut: specifications, model and files