Old Mine Cut Sapphire: an antique cushion that loses half its light

Brilliance 50 · Fire 36 · Scintillation 81 · in our census, where the T73 scores 94 · 37 · 80 in sapphire

The broad antique cushion in sapphire: half the light leaves through the back, and the face shows it.

See it in the simulatorGet the files
The Old Mine Cut in sapphire, rendered at an angle in our 3D Gemstone Simulator under studio light
Rendered in our 3D Gemstone Simulator from the Old Mine Cut model, 1.00 ct, studio light.

Old Mine Cut Sapphire

The Old Mine's wide 60.3% table and 44.38° pavilion already leak a third of the light in diamond. Sapphire, with a critical angle near 34.6°, takes that to half.

It is also heavier than diamond for its size, as every sapphire is.

Of the five antique cuts in sapphire, the Old Mine ranks third for light: behind the Old European (78) and the Mazarin (58), ahead of the Peruzzi and the Old Single. Its pavilion, at 44.38°, sits well above sapphire's guide minimum of 36.4°, so the loss comes with the design, and a different design is the remedy the numbers support.

Is sapphire good in an Old Mine cut? Pros and cons

Pros

None that we measure.

Cons

Compared with the T73 Round Brilliant in sapphire and with the Old Mine 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 Old Mine 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.

Performance wheel: Old Mine Cut in sapphire, against the T73 Round Brilliant in sapphire as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−17Brilliance−44Fire−1Scintillation+1Spread−2Symmetry−10Shape-norm−24Tilt+25

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

  • Global62, the comparison 79, difference −17
  • Brilliance50, the comparison 94, difference −44
  • Fire36, the comparison 37, difference −1
  • Scintillation81, the comparison 80, difference +1
  • Spread98, the comparison 100, difference −2
  • Symmetry90, the comparison 100, difference −10
  • Shape-norm78, the comparison 102, difference −24
  • Tilt100, the comparison 75, difference +25
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 sapphire gains in an Old Mine cut

No score beats a baseline by our margins. Tilt reads 100 because there is so little light to lose, and scintillation is level with the T73 at 81. The outline is its appeal.

Where the Old Mine falls short in sapphire

Half the T73's light

Brilliance 50 against 94 for the T73 Round Brilliant in sapphire: 44 points lower

Grey covers the flanks and the ends of the face-up map; colour survives in a cross through the middle.

Old mine cut in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 50)

Old Mine Cut in sapphire · Brilliance 50

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)

T73 Round Brilliant in sapphire · 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: In sapphire the modern Cushion Cut returns 88.

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

Half the light leaks

Leakage 49 against 5 for the T73 Round Brilliant in sapphire: 44 points higher

Nearly half the light in our census, 49%, leaves through the pavilion; the T73 in sapphire loses 5%.

Old Mine Cut in sapphire · Leakage 49

Old mine cut in sapphire tilted 0 degrees: Light Return map, 50% of the face leaking0° · 50% leak
Old mine cut in sapphire tilted 10 degrees: Light Return map, 46% of the face leaking10° · 46% leak
Old mine cut in sapphire tilted 20 degrees: Light Return map, 37% of the face leaking20° · 37% leak
Old mine cut in sapphire tilted 30 degrees: Light Return map, 37% of the face leaking30° · 37% leak

T73 Round Brilliant in sapphire · Leakage 5

T73 round brilliant in sapphire tilted 0 degrees: Light Return map, 1% of the face leaking0° · 1% leak
T73 round brilliant in sapphire tilted 10 degrees: Light Return map, 10% of the face leaking10° · 10% leak
T73 round brilliant in sapphire tilted 20 degrees: Light Return map, 29% of the face leaking20° · 29% leak
T73 round brilliant in sapphire tilted 30 degrees: Light Return map, 30% of the face leaking30° · 30% leak
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: Not by steepening: the mains are at 44.38°, above sapphire's 36.4° guide minimum. The Cushion Cut leaks 11%.

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

Half the fire of the diamond version

Fire 36 against 72 for the Old Mine Cut in diamond: 36 points lower

Fire 36 against 72 for the same cut in diamond: sapphire's dispersion is under half of diamond's.

Old mine cut in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 36)

Old Mine Cut in sapphire · Fire 36

Old mine cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 72)

Old Mine Cut in diamond · Fire 72

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.

What helps: The material sets the limit; the Oval Cut reaches 74 in sapphire.

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

Heavier than diamond

1.37 ct at 6.5 mm, against 1.21 ct for the same cut in diamond (+14%)

Sapphire's specific gravity is 4.00 against 3.52, about 14% more weight for the same size.

Sapphire1.37 ctDiamond1.21 ct
A Old Mine Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: None in the cut; choose by millimetres.

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

Who an Old Mine sapphire suits

An Old Mine sapphire suits a collector after the antique outline in colour, not a bright stone.

For light in a cushion, the modern Cushion Cut; for an antique round, the Old European Cut Sapphire.

If the outline is a must, compare it with our modern Cushion Cut in sapphire before cutting: 88 brilliance against 50.

Its 74 facets keep the sparkle level with the T73, scintillation 81; it is the light that falls away.

Old Mine Cut Sapphire: questions

Is the Old Mine cut good for sapphire?

It loses half its light in our census: 49% leakage and Brilliance 50 against 94 for the T73.

Old Mine or Old European for a sapphire?

The Old European by a wide margin: Brilliance 78 against 50, leakage 22% against 49%.

What does a 6.5 mm Old Mine sapphire weigh?

1.37 ct, where a diamond of the same size is 1.21 ct.

Does an Old Mine sapphire have any fire?

Some: Fire 36, about the T73's 37 in sapphire, against 72 for the same cut in diamond.

Get the Old Mine Cut files

6 formatsMillimetresWatertight

Old Mine Cut 3D files

The Old Mine Cut as exact geometry: 74 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

Old Mine Cut cutting files

The Old Mine Cut as a faceting design: 58 + 16 girdles = 74 facets, 96 index, 4-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 Old Mine Cut: specifications, model and files

Other cuts in sapphire

The Old Mine Cut in other gemstones