Radiant Square Cut Ruby: a steady square brilliant with modest light and little fire

Brilliance 76 · Fire 25 · Scintillation 66 · in our census, where the T73 scores 94 · 37 · 80 in ruby

A square radiant in ruby holds its light well when tipped, but it starts with less than a round and scores Fire 25 to the diamond version's 62.

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

Radiant Square Cut Ruby

A square with its corners cropped, filled with a brilliant facet plan: that is the square radiant. Ours has 49 facets, a 34.64° pavilion and a deep 72.8% total depth.

In ruby it returns more light than the same cut in diamond, 76 against 72, and less than the T73. Its fire is among the lowest we measure in ruby.

The pavilion, 34.64°, sits just above ruby's critical angle of 34.6° and below the 36.4° guide minimum for round designs.

Square radiant ruby: good or not? Pros and cons

Pros

None by our margins: its high Tilt rides on modest light.

Cons

Compared with the T73 Round Brilliant in ruby and with the Radiant Square 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 Radiant Square 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.

Performance wheel: Radiant Square Cut in ruby, against the T73 Round Brilliant in ruby as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−10Brilliance−18Fire−12Scintillation−14Spread+1Symmetry0Shape-norm−14Tilt+10

Against the T73 Round Brilliant in ruby: ahead on 2, level on 1, behind on 5.

  • Global69, the comparison 79, difference −10
  • Brilliance76, the comparison 94, difference −18
  • Fire25, the comparison 37, difference −12
  • Scintillation66, the comparison 80, difference −14
  • Spread101, the comparison 100, difference +1
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm88, the comparison 102, difference −14
  • Tilt85, the comparison 75, difference +10
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 ruby gains in a square radiant

Tilt beats the T73 and Brilliance beats the diamond version, 76 to 72, yet neither is a pro: brilliance trails the T73 by more, so it counts as a con. Tilt, 85 to the round's 75, would need brilliance within five points of the T73's to count as a pro, and against the diamond version's 90 it falls behind. Symmetry is level at 100. What it offers is a square brilliant face with cropped corners.

Where the square radiant falls short in ruby

Much less fire than a diamond square radiant

Fire 25 against 62 for the Radiant Square Cut in diamond: 37 points lower

Fire 25 against 62 for the same cut in diamond, and low even by ruby standards: the T73 in ruby scores 37, more than this stone.

Radiant square cut in ruby face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 25)

Radiant Square Cut in ruby · Fire 25

Radiant square cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 62)

Radiant Square Cut in diamond · Fire 62

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: Among ruby cuts that keep close to the T73's light, the Trilliant Cut Ruby shows the most fire, 52.

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

Less light than a round ruby

Brilliance 76 against 94 for the T73 Round Brilliant in ruby: 18 points lower

Light reaching the cropped corners meets facets at other angles than a round's, and the census loses more of it. Against the diamond version, though, the ruby comes out ahead.

Radiant square cut in ruby face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 76)

Radiant Square Cut in ruby · Brilliance 76

T73 round brilliant in ruby 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 ruby · 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: The pavilion is below the 36.4° guide minimum for round designs, but we have no measurements of a steeper version. For a square brilliant with more light, the Cushion Cut Ruby returns 88.

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

A fifth of the light leaks

Leakage 20 against 5 for the T73 Round Brilliant in ruby: 15 points higher

Our census counts 20% of its light going out through the pavilion, where the T73 loses 5%. With the pavilion barely above the critical angle, light from straight above is close to the point where it would pass through.

Radiant Square Cut in ruby · Leakage 20

Radiant square cut in ruby tilted 0 degrees: Light Return map, 18% of the face leaking0° · 18% leak
Radiant square cut in ruby tilted 10 degrees: Light Return map, 24% of the face leaking10° · 24% leak
Radiant square cut in ruby tilted 20 degrees: Light Return map, 24% of the face leaking20° · 24% leak
Radiant square cut in ruby tilted 30 degrees: Light Return map, 37% of the face leaking30° · 37% leak

T73 Round Brilliant in ruby · Leakage 5

T73 round brilliant in ruby tilted 0 degrees: Light Return map, 1% of the face leaking0° · 1% leak
T73 round brilliant in ruby tilted 10 degrees: Light Return map, 10% of the face leaking10° · 10% leak
T73 round brilliant in ruby tilted 20 degrees: Light Return map, 29% of the face leaking20° · 29% leak
T73 round brilliant in ruby 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: A larger radiant square leaks the same share. The Cushion Cut Ruby lets out 11%.

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

Fewer flashes than a round

Scintillation 66 against 80 for the T73 Round Brilliant in ruby: 14 points lower

49 facets against the T73's 73, and the scintillation score follows the facet plan.

Radiant Square Cut · 49 facets · Scintillation 66

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: On a square outline, the Cushion Cut Ruby scores 85.

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

Who a square radiant ruby suits

The square radiant suits a ruby seen at many angles, in a setting where its cropped corners are safer than a princess's points. Face-up it sits in the upper half of our ruby cuts for light and near the bottom for fire.

For a square ruby with more light, the brilliant Cushion Cut Ruby. For sharp corners, the Princess Cut Ruby, though it returns less light, 68; for more colour and more light together, the Trilliant Cut Ruby, with Fire 52 and Brilliance 86.

Radiant Square Cut Ruby: questions

Is a square radiant cut good for ruby?

It returns 76 for brilliance against the T73's 94, leaks 20%, and holds its light well when tipped, Tilt 85.

Square radiant or princess cut ruby?

The square radiant returns more light (76 against 68) and leaks less (20% against 27%); the princess has more fire (52 against 25).

Does a square radiant ruby have fire?

Little: 25 in our census, below the T73's 37 in ruby and far below the 62 of the same cut in diamond.

What does a 6.5 mm square radiant ruby weigh?

1.84 ct from our model's volume; a diamond of the same cut and size is 1.62 ct.

Get the Radiant Square Cut files

6 formatsMillimetresWatertight

Radiant Square Cut 3D files

The Radiant Square Cut as exact geometry: 49 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

Radiant Square Cut cutting files

The Radiant Square Cut as a faceting design: 41 + 8 girdles = 49 facets, 96 index, 4-fold 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

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More gemstones and cuts

Ruby: optical properties and the top ten cuts · The Radiant Square Cut: specifications, model and files

Other cuts in ruby

The Radiant Square Cut in other gemstones