Brilliance 41 · Fire 58 · Scintillation 63 · in our census, where the T73 scores 94 · 37 · 80 in ruby
Square corners and wide steps: in ruby the rectangle shows as much face for its weight as any cut we measure, level with the marquise, and loses about half its light through the back.
Wide, clean steps on a plain rectangle with square corners: an emerald cut with nothing cropped. Ours has 45 facets, a length-to-width ratio of 1.506, a 33.48° pavilion and 62.0% depth.
Its two pros are large and real: more face per carat than the T73, and more fire. Its cons are larger. 52% of its light leaves through the pavilion, and our emerald cut, on nearly the same length-to-width ratio, keeps much more of it: 65 for brilliance against 41.
Compared with the T73 Round Brilliant in ruby 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.
At a glance: the Rectangle 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, level on 2, behind on 4.
Fire 58 against 37 for the T73 Round Brilliant in ruby: 21 points higher
Wide, flat steps return light in broad planes, and the census finds a larger share of that light split into colour than in the T73. In diamond the same rectangle scores 77.
Rectangle Cut in ruby · Fire 58
T73 Round Brilliant in ruby · Fire 37
Face-up size 121 against 100 for the T73 Round Brilliant in ruby (T73 = 100): 21% more face-up area for the same weight
Square corners keep the area that an emerald cut trims away. Only the marquise matches it among the cuts we measure in ruby; the emerald cut, on almost the same length-to-width ratio but cut deeper, reaches 105. The figure comes from the model's outline and is the same in every stone.
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
Try it yourself: See its size at 1.00 ct in ruby in the 3D Gemstone Simulator
Brilliance 41 against 94 for the T73 Round Brilliant in ruby: 53 points lower
The pavilion is cut at 33.48°, below ruby's critical angle of 34.6°: light arriving straight through the table meets it at an angle it can pass through.
Rectangle Cut in ruby · Brilliance 41
T73 Round Brilliant in ruby · Brilliance 94
What helps: The Emerald Cut Ruby, with a steeper pavilion, returns 65. We have no measurements of a rectangle cut that way, so we cannot promise what one would give.
Try it yourself: Open this Light Return map in the simulator
Leakage 52 against 5 for the T73 Round Brilliant in ruby: 47 points higher
52% leaves through the back in our census, against 5% for the T73 and 32% for the rectangle in diamond. Of the step cuts we measure in ruby, only DG-Elongated Hexagon leaks more.
Rectangle Cut in ruby · Leakage 52
T73 Round Brilliant in ruby · Leakage 5
What helps: A smaller rectangle leaks the same share. The Emerald Cut Ruby lets out 25%.
Try it yourself: Tilt it yourself in the simulator's light map
Scintillation 63 against 80 for the T73 Round Brilliant in ruby: 17 points lower
Fewer facets than the T73: 45 in long parallel rows, against 73 in a brilliant plan.
Rectangle Cut · 45 facets · Scintillation 63
T73 Round Brilliant · 73 facets · Scintillation 80
Try it yourself: Compare the Scintillation spoke in the Cut Performance Wheel
2.39 ct at 6.5 mm, against 2.10 ct for the same cut in diamond (+14%)
Corundum, at a specific gravity of 4.00, is denser than diamond at 3.52, so the same rectangle weighs 14% more in ruby.
What helps: Choose by millimetres; the large face per carat then works in your favour.
Try it yourself: Weights in all seven gemstones on the Rectangle Cut page
Pick the rectangle when face per carat is the point: a ruby bar, an east-west setting, or a row of side stones whose square corners sit flush. A larger share of its returned light is split into colour than in the T73, Fire 58 against 37, but it returns little light: Brilliance 41.
For a similar rectangle with far more light, the Emerald Cut Ruby, and DG-M5 Ruby if light outranks shape altogether.
Per carat, yes: its outline covers 121 against 100 for the T73, level with the marquise for the most of any ruby cut we measure.
The emerald cut returns more light (65 against 41) and leaks less (25% against 52%); the rectangle faces up larger per carat (121 against 105) and has more fire.
For face-up size and fire it scores well, 121 and 58. For light it is weak: 52% leaks through the pavilion.
Around 2.39 ct, or 2.10 ct for the same rectangle in diamond.
The Rectangle Cut as exact geometry: 45 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The Rectangle Cut as a faceting design: 41 + 4 girdles = 45 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 Rectangle Cut: specifications, model and files