Princess Cut Amethyst: Pros, Cons & Light Leakage

The princess is a square brilliant with sharp corners and chevron pavilion facets. Our model has 85 facets in its cutting design, a 41.94° pavilion and 68.5% depth, deeper than the T73's 61.7%.

That pavilion clears amethyst's 40.4° guide minimum. Even in diamond the same model returns only 57. In amethyst it returns 45 and leaks far more.

Per carat it faces up within a point of the round, 101 against 100: no real gain in size, and no loss.

Is a princess cut good for amethyst? Pros and cons

Pros

Lighter than a diamond princess 1.11 vs 1.48 ct

Cons

Under a third of the diamond princess's fire 25 vs 83
Half the light leaks 50 vs 18
Under two thirds of the T73's light 45 vs 72
A little less steady when tipped than in diamond 82 vs 89

Compared with the T73 Round Brilliant in amethyst and with the Princess 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 Princess 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: ahead on 1, level on 1, behind on 6.

Global56, the comparison 70, difference −14
Brilliance45, the comparison 72, difference −27
Fire25, the comparison 36, difference −11
Scintillation78, the comparison 80, difference −2
Spread95, the comparison 100, difference −5
Symmetry100, the comparison 100, difference 0
Shape-norm70, the comparison 77, difference −7
Tilt82, the comparison 80, difference +2

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 amethyst gains in a princess cut

Lighter than a diamond princess

1.11 ct at 6.5 mm, against 1.48 ct for the same cut in diamond (−25%)

Specific gravity 2.65 against 3.52: a princess of the same millimetres weighs a quarter less in quartz. It is the only gain large enough to count as a pro on this page.

A Princess 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 Princess Cut page

The catch with a princess amethyst

Under a third of the diamond princess's fire

Fire 25 against 83 for the Princess Cut in diamond: 58 points lower

Our census gives the diamond princess 83 for fire and this amethyst one 25, below the T73's 36 in quartz too.

Princess cut in amethyst face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 25) — 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.

Princess cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 83) — 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: For more fire, look past the princess: of the cuts within ten points of the T73's brilliance in amethyst, DG-Anteros Amethyst carries the most, 54.

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

Half the light leaks

Leakage 50 against 18 for the Princess Cut in diamond: 32 points higher

In diamond the princess loses under a fifth of its light through the back; in quartz, half. The picture's diamond strip stays near a quarter grey across its frames, rising a little in the last.

Princess cut in amethyst tilted 0 degrees: Light Return map, 43% 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.

Princess cut in amethyst tilted 10 degrees: Light Return map, 57% 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: No steeper princess is in our census, so we offer none. Among square outlines in amethyst, the Square Cut Amethyst brilliant leaks least: 29%.

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

Under two thirds of the T73's light

Brilliance 45 against 72 for the T73 Round Brilliant in amethyst: 27 points lower

A square's corners send light down at angles a round never meets, and quartz's critical angle of 40.4° lets more of it through.

Princess cut in amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 45) — 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 amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 72) — 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 brighter square, the Cushion Cut Amethyst returns 69 and the Square Cut Amethyst 65.

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

A little less steady when tipped than in diamond

Tilt 82 against 89 for the Princess Cut in diamond: 7 points lower

Tipped by 20°, the amethyst princess keeps slightly less of its face-up light than the diamond one. Against the T73 in amethyst it holds a touch more, 82 against 80, so this con is set against diamond only.

What helps: The Square Cut Amethyst holds 84 at 20°, a little more, with more light to hold.

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

Who a princess amethyst suits

The princess suits an amethyst ring or earrings where crisp square corners are the look and fire is not expected. Its points are its weak spots, and quartz at hardness 7 needs them protected.

Choose it for the outline, not for light or fire. For a brighter square in amethyst, the Square Cut Amethyst brilliant or the Cushion Cut Amethyst.

Princess Cut Amethyst: questions

Is a princess cut good for amethyst?

Not for light: in our census it returns 45 where the T73 returns 72, and 50% of the light leaks. Its facet plan sparkles nearly as much as the round's.

Princess or square cut amethyst?

The square brilliant wins on light (65 against 45), leakage (29% against 50%) and fire (34 against 25). Sparkle is level.

Does a princess amethyst have fire?

Not much: 25 in our census, against 36 for the T73 in amethyst and 83 for a diamond princess.

How heavy is a 6.5 mm princess amethyst?

1.11 ct, where a diamond princess would be 1.48 ct.

Get the Princess Cut files

6 formatsMillimetresWatertight

Princess Cut 3D files

The Princess Cut as exact geometry: 93 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

Princess Cut cutting files

The Princess Cut as a faceting design: 81 + 4 girdles = 85 facets, 96 index, 4-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

Amethyst: optical properties and the top ten cuts · The Princess Cut: specifications, model and files

Princess Cut Amethyst: sharp square corners at three quarters of diamond's weight