Brilliance 53 · Fire 32 · Scintillation 72 · in our census, where the T73 scores 72 · 36 · 80 in amethyst
The emerald cut keeps nearly all of its diamond brilliance in quartz, 53 against 55. What it gives up is fire, and its hold on light once the stone tips.
The emerald cut is a rectangular step cut with cropped corners and a long, open table. Ours has 57 facets on an outline 1.5 times as long as wide, a 41.0° pavilion and 68.6% depth.
Quartz costs it little light in our census: 55 in diamond, 53 here. Its pavilion sits above amethyst's 40.4° guide minimum.
The catch lies elsewhere. Its fire falls from 87 in diamond to 32 in quartz, and tipped by 20° this model keeps less of its light than any other cut we measure in amethyst.
Compared with the T73 Round Brilliant in amethyst and with the Emerald 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 Emerald Cut in amethyst (white) against the T73 Round Brilliant in amethyst (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 amethyst: behind on 8.
1.74 ct at 6.5 mm, against 2.31 ct for the same cut in diamond (−25%)
Quartz is the lighter material, 2.65 against 3.52 in specific gravity, so an emerald cut of given millimetres weighs about three quarters as much in amethyst as in diamond.
Try it yourself: Weights in all seven gemstones on the Emerald Cut page
Face-up size 105 against 100 for the T73 Round Brilliant in amethyst (T73 = 100): 5% more face-up area for the same weight
At the same weight, the emerald cut's outline covers more area than the T73's. The gain is small, and it holds in any stone, because it is measured from the model's shape alone.
Emerald Cut · 8.11 x 5.41 mm at 1.00 ct · Face-up size 105
T73 Round Brilliant · 7.12 mm at 1.00 ct · Face-up size 100
Try it yourself: See its size at 1.00 ct in amethyst in the 3D Gemstone Simulator
Fire 32 against 87 for the Emerald Cut in diamond: 55 points lower
In diamond the broad steps score 87 for fire. In amethyst the same steps score 32, a few points under the T73's 36 as well. The census swaps the whole material between the two stones, so it does not pin the drop on dispersion alone.
Emerald Cut in amethyst · Fire 32
Emerald Cut in diamond · Fire 87
What helps: Of the cuts within ten points of the T73's brilliance in amethyst, DG-Anteros Amethyst shows the most fire: 54.
Symmetry 64 against 100 for the T73 Round Brilliant in amethyst: 36 points lower
Our symmetry score rewards pavilion facets that repeat evenly around a design, and only the baguette and the trilliant score lower in amethyst. Neither the long outline nor the cropped corners explains it: the rectangle has the one and the emerald square the other, and both score 100. The cost lies in how this plan lays out its pavilion steps.
Emerald Cut · 57 facets · Symmetry 64
T73 Round Brilliant · 73 facets · Symmetry 100
What helps: It is the design. The Emerald Square Cut Amethyst keeps the steps and cropped corners on a square and scores 100.
Try it yourself: Compare the Symmetry spoke in the Cut Performance Wheel
Tilt 54 against 83 for the Emerald Cut in diamond: 29 points lower
No cut in our amethyst census keeps less of its face-up light when tipped by 20°. The diamond emerald cut keeps 83; quartz's critical angle of 40.4°, far wider than diamond's, lets more light through the steps as the view moves.
Emerald Cut in amethyst · Tilt 54
Emerald Cut in diamond · Tilt 83
What helps: The Octagon Cut Amethyst holds 83 when tipped and the Square Cut Amethyst brilliant 84, both with more light to hold.
Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel
Brilliance 53 against 72 for the T73 Round Brilliant in amethyst: 19 points lower
Its steps clear the guide minimum, so a shallow angle is not the reason. This one returns about three quarters of the round's light in quartz, 53 against 72.
Emerald Cut in amethyst · Brilliance 53
T73 Round Brilliant in amethyst · Brilliance 72
What helps: We have not measured a steeper emerald cut, so we promise none. No rectangular cut we measure in amethyst returns more; for more light, the Cushion Cut Amethyst gives 69.
Try it yourself: Open this Light Return map in the simulator
Choose the emerald cut in amethyst when the long, open table is the point: an evenly coloured stone shown plainly, in a ring or pendant seen mostly face-up. No other rectangle we measure in quartz returns as much light.
If the stone will swing and tip, as in drop earrings, the Octagon Cut Amethyst holds its light better. Our brightest amethyst cut of all is DG-M5 Amethyst.
Fairly: Brilliance 53, close to the 55 it scores in diamond, and Face-up size 105, though among step cuts the octagon, the emerald square and the Asscher return more light. Tipped, it holds its light poorly: Tilt 54.
Little: 32 in our census, against 36 for the T73 in amethyst and 87 for the same cut in diamond.
The emerald cut returns far more light (53 against 20) and leaks less (41% against 76%); the radiant faces up larger per carat (118 against 105) and has more fire.
1.74 ct. The diamond version: 2.31 ct.
The Emerald Cut as exact geometry: 57 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The Emerald Cut as a faceting design: 49 + 8 girdles = 57 facets, 64 index, 2-fold mirror-image symmetry, ready for the machine.
Questions before you buy? Email us.
Amethyst: optical properties and the top ten cuts · The Emerald Cut: specifications, model and files