Rectangle Cut Sapphire: the joint-largest face for its weight we measure

Brilliance 41 · Fire 58 · Scintillation 63 · in our census, where the T73 scores 94 · 37 · 80 in sapphire

A plain step-cut rectangle with square corners: per carat it shows as much face as any cut we measure, and lets just over half its light out through the back.

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

Rectangle Cut Sapphire

The rectangle is a step cut with wide steps and square corners, simpler than an emerald cut. Ours measures 1.506 to 1 and 62.0% deep, and carries 45 facets on a 33.48° pavilion figure.

That pavilion figure sits under sapphire's critical angle of 34.6° and its 36.4° guide minimum, and the census finds the light to match.

Against the T73 Round Brilliant it wins on size and on fire. It loses on light, both to the T73 and to the same rectangle in diamond.

Should a sapphire be cut as a rectangle? Pros and cons

Pros

Cons

Compared with the T73 Round Brilliant in sapphire and with the Rectangle Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 4% (face-up size per carat) 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 Rectangle 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: Rectangle 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−19Brilliance−53Fire+21Scintillation−17Spread0Symmetry0Shape-norm−47Tilt+6

Against the T73 Round Brilliant in sapphire: ahead on 2, level on 2, behind on 4.

  • Global60, the comparison 79, difference −19
  • Brilliance41, the comparison 94, difference −53
  • Fire58, the comparison 37, difference +21
  • Scintillation63, the comparison 80, difference −17
  • Spread100, the comparison 100, difference 0
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm55, the comparison 102, difference −47
  • Tilt81, the comparison 75, difference +6
Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring. Spread is the census's estimate from depth alone; the face-up size in the pros and cons is measured from each model's outline.
Open it in the Cut Performance Wheel

What a sapphire gains as a rectangle

More fire than the round

Fire 58 against 37 for the T73 Round Brilliant in sapphire: 21 points higher

Fire 58 against 37 for the T73 in sapphire. The diamond rectangle shows more, 77; the census changes the whole material, so it does not split that gap by cause.

Rectangle cut in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 58)

Rectangle Cut in sapphire · Fire 58

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)

T73 Round Brilliant in sapphire · Fire 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

The largest face for its weight, with the marquise

Face-up size 121 against 100 for the T73 Round Brilliant in sapphire (T73 = 100): 21% more face-up area for the same weight

Measured from its outline, a carat of this rectangle covers as much area as any cut we measure; only the marquise matches it.

Rectangle Cut · 7.32 x 4.86 mm at 1.00 ct · Face-up size 121

T73 Round Brilliant · 6.21 mm at 1.00 ct · Face-up size 100

Both stones weigh 1.00 ct in sapphire and are drawn to the same scale in millimetres, from each cut's own model. Face-up size is the outline's area per carat, with the T73 at 100: a deeper stone, or a rounder outline, spreads less area for its weight.

Try it yourself: See its size at 1.00 ct in sapphire in the 3D Gemstone Simulator

The catch with a rectangle sapphire

Under half the T73's light

Brilliance 41 against 94 for the T73 Round Brilliant in sapphire: 53 points lower

Brilliance 41 against 94. The same rectangle in diamond returns 50, so the cut is dim in both stones and dimmer in sapphire.

Rectangle cut in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 41)

Rectangle Cut in sapphire · Brilliance 41

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: For a step-cut rectangle with more light, the Emerald Cut Sapphire returns 65.

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

Just over half the light leaks

Leakage 52 against 5 for the T73 Round Brilliant in sapphire: 47 points higher

52% of the light in our census goes out through the pavilion, against 5% for the T73 and 32% for the diamond rectangle.

Rectangle Cut in sapphire · Leakage 52

Rectangle cut in sapphire tilted 0 degrees: Light Return map, 56% of the face leaking0° · 56% leak
Rectangle cut in sapphire tilted 10 degrees: Light Return map, 56% of the face leaking10° · 56% leak
Rectangle cut in sapphire tilted 20 degrees: Light Return map, 61% of the face leaking20° · 61% leak
Rectangle cut in sapphire tilted 30 degrees: Light Return map, 63% of the face leaking30° · 63% 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: Leak share is fixed by the angles, whatever the size. The Emerald Cut Sapphire leaks 25%.

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

Fewer flashes than a round

Scintillation 63 against 80 for the T73 Round Brilliant in sapphire: 17 points lower

Scintillation 63 against 80: 45 broad step facets against the T73's 73 smaller ones.

Rectangle Cut · 45 facets · Scintillation 63

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.

What helps: Our Emerald Cut Sapphire model reaches 72 for scintillation.

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

Heavier than diamond at the same width

2.39 ct at 6.5 mm, against 2.10 ct for the same cut in diamond (+14%)

A 6.5 mm wide rectangle comes to 2.39 ct in sapphire and 2.10 ct in diamond, from the model's volume and each stone's density.

Sapphire2.39 ctDiamond2.10 ct
A Rectangle Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Buy it by length and width; per carat it already shows more face than a round.

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

Who a rectangle sapphire suits

The rectangle suits bar settings, side stones and minimalist designs, where a clean outline and a large face per carat count for more than light.

If you want a brighter rectangle, the Emerald Cut Sapphire returns more light and leaks about half as much. A round such as DG-M5 Sapphire returns more than twice its light.

For cutters, the 33.48° pavilion figure is below sapphire's 36.4° guide minimum. We have no measurement of a steeper rectangle, so we cannot say how much light one would recover.

Rectangle Cut Sapphire: questions

Is a rectangle cut good for sapphire?

For size, yes: Face-up size 121, level with the marquise at the top of our census. For light it is weak: Brilliance 41, with 52% leaking.

Rectangle or emerald cut for a sapphire?

The emerald cut: Brilliance 65 against 41 and leakage 25% against 52%. The rectangle has more fire (58 against 47) and faces up larger.

What does a 6.5 mm wide rectangle sapphire weigh?

Our 1.506 to 1 model comes to 2.39 ct at that width; in diamond the same rectangle is 2.10 ct.

Get the Rectangle Cut files

6 formatsMillimetresWatertight

Rectangle Cut 3D files

The Rectangle Cut as exact geometry: 45 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

Rectangle Cut cutting files

The Rectangle Cut as a faceting design: 41 + 4 girdles = 45 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 Rectangle Cut: specifications, model and files

Other cuts in sapphire

The Rectangle Cut in other gemstones