Triangle Cut Emerald: Pros, Cons & Fire

The triangle is a plain equilateral cut: two crown tiers over three pavilion tiers, nothing spare. Our model pairs a 60.0% table with a 35.3° crown and a 41.76° pavilion, 55.4% from table to culet. The site's cut notes recommend it to new cutters.

Its pavilion is steeper than emerald's 39.4° guide minimum, so the light it loses does not come from a shallow pavilion. In diamond the same triangle returns 53; in emerald, 27.

Two of its figures are the extremes of our emerald pages: the lowest Scintillation and the smallest Face-up size of any cut we measure.

Is a triangle cut emerald worth cutting? Pros and cons

Pros

More fire than a round emerald 65 vs 39
Lighter than a diamond triangle 0.61 vs 0.79 ct

Cons

Much less light than a round 27 vs 78
The fewest flashes we measure in emerald 34 vs 80
Nearly twice the T73's leakage 43 vs 22
A smaller face for its weight than a round 89 vs 100

Compared with the T73 Round Brilliant in emerald and with the Triangle 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 Triangle Cut in emerald (white) against the T73 Round Brilliant in emerald (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 emerald: ahead on 3, level on 1, behind on 4.

Global57, the comparison 73, difference −16
Brilliance27, the comparison 78, difference −51
Fire65, the comparison 39, difference +26
Scintillation34, the comparison 80, difference −46
Spread104, the comparison 100, difference +4
Symmetry100, the comparison 100, difference 0
Shape-norm36, the comparison 84, difference −48
Tilt100, the comparison 77, difference +23

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 emerald gains in a triangle cut

More fire than a round emerald

Fire 65 against 39 for the T73 Round Brilliant in emerald: 26 points higher

65 against 39 for the T73: few, large facets, and what light comes back is split into broad colour. In diamond the triangle scores 86; emerald's low dispersion holds it below that.

Triangle cut in emerald face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 65) — 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.

T73 round brilliant in emerald face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 39) — 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

Lighter than a diamond triangle

0.61 ct at 6.5 mm, against 0.79 ct for the same cut in diamond (−23%)

Each 6.5 mm triangle comes to 0.61 ct in emerald and 0.79 ct in diamond, the difference between beryl at 2.72 and diamond at 3.52.

A Triangle Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

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

The catch with a triangle emerald

Much less light than a round

Brilliance 27 against 78 for the T73 Round Brilliant in emerald: 51 points lower

27 against 78. With 19 facets, light gets few chances to turn back towards the eye before it meets a facet it can pass through. Emerald roughly halves the diamond version's figure.

Triangle cut in emerald face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 27) — 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.

T73 round brilliant in emerald face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 78) — 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: Steepening is not the fix: the pavilion already sits at 41.76°, above 39.4°. Among triangles in emerald, the Trilliant Cut Emerald returns 68 and the Trillion Cut Emerald 63.

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

The fewest flashes we measure in emerald

Scintillation 34 against 80 for the T73 Round Brilliant in emerald: 46 points lower

So few facets cannot flash like a round: the triangle has 19, the T73 73. No cut we measure in emerald scores lower than this triangle's 34, and the figure is the same in diamond.

Triangle Cut · 19 facets · Scintillation 34

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: Only more facets raise it. The Trillion Cut Emerald scores 80 on a three-sided outline.

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

Nearly twice the T73's leakage

Leakage 43 against 22 for the T73 Round Brilliant in emerald: 21 points higher

43% of the light in our census leaves through the pavilion, against 22% for the T73 in emerald and 25% for the triangle in diamond.

Triangle cut in emerald tilted 0 degrees: Light Return map, 41% of the face leaking — 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.

Triangle cut in emerald tilted 10 degrees: Light Return map, 49% of the face leaking — 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: Size does not change it. The Trillion Cut Emerald leaks 27% in emerald.

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

A smaller face for its weight than a round

Face-up size 89 against 100 for the T73 Round Brilliant in emerald (T73 = 100): 11% less face-up area for the same weight

Face-up size is area per carat. The triangle's depth is quoted against its width, but a triangle covers only half the rectangle around it, so for the face it shows the stone is deep. It is the smallest figure on our emerald pages, and it is the same in every stone.

Triangle Cut · 8.84 x 7.65 mm at 1.00 ct · Face-up size 89

T73 Round Brilliant · 7.06 mm at 1.00 ct · Face-up size 100

Both stones weigh 1.00 ct in emerald 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.

What helps: The Trillion Cut Emerald faces up at 100, level with the T73. Otherwise, compare stones by millimetres: a 6.5 mm triangle weighs 0.61 ct here.

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

Who a triangle emerald suits

The triangle suits a first emerald on the faceting machine, or an accent stone where a few bold flashes of colour are wanted. It is not a cut for light: of the triangles we measure in emerald, it returns the least.

For a three-sided emerald with far more light and sparkle, the Trillion Cut Emerald or the Trilliant Cut Emerald; both give up fire to the triangle.

Triangle Cut Emerald: questions

Is a triangle cut good for emerald?

Only if fire is what you want: 65 against 39 for a round. Its light, 27, and its sparkle, 34, are both far below the T73's.

Triangle or trillion cut for an emerald?

The trillion returns more light (63 against 27), sparkles more (80 against 34) and faces up larger per carat (100 against 89). The triangle has more fire.

Is a triangle emerald easy to cut?

It has 19 facets, the fewest on our emerald pages, and the site's cut notes call it approachable for new cutters.

What does a 6.5 mm triangle emerald weigh?

0.61 ct in our model. In diamond the same triangle is 0.79 ct.

Get the Triangle Cut files

6 formatsMillimetresWatertight

Triangle Cut 3D files

The Triangle Cut as exact geometry: 19 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

Triangle Cut cutting files

The Triangle Cut as a faceting design: 16 + 3 girdles = 19 facets, 96 index, 3-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

Questions before you buy? Email us.

More gemstones and cuts

Emerald: optical properties and the top ten cuts · The Triangle Cut: specifications, model and files

Triangle Cut Emerald: more fire than a round, with the fewest facets we measure