Free reference

The Diagram Library.

Classic faceting designs in the public domain — with full cutting schedules you can work from right here. These aren't Gem Beam originals; they're the standards every faceter should know, collected in one place.

New to cutting? Start with the Standard Round Brilliant. Chasing ideal proportions? That's Tolkowsky. Want the hall-of-mirrors look? Emerald Cut.

01 / Round

Standard Round
Brilliant #

The 58-facet round brilliant every faceter learns first. This is the US Faceters Guild standard version, spec'd here for quartz (RI 1.54) — raise the pavilion angles a couple of degrees for higher-RI material.

Facets
58 + girdle
Table
~52%
Symmetry
8-fold mirror
Outline
Round
Index gear
96
Spec'd for
Quartz · RI 1.54
Cut the pavilion breaks to a temporary center point, level the girdle at 90°, then bring the mains to meet. On the crown, the table needs no meets — just cut it level and to size.
Cutting schedule

Pavilion

PB144.0°03 09 15 21 27 33 39 45 51 57 63 69 75 81 87 93 · 16 breaks to temp center
G90.0°girdle — cut to meet PB1
PM142.0°96 12 24 36 48 60 72 84 · 8 mains to meet breaks + girdle

Crown

CB34.0°03 09 15 21 27 33 39 45 51 57 63 69 75 81 87 93 · 16 breaks to level girdle
CM28.0°96 12 24 36 48 60 72 84 · 8 mains to meet breaks + girdle
S15.0°06 18 30 42 54 66 78 90 · 8 stars
F10.0°06 18 30 42 54 66 78 90 · 8 upper-girdle facets
T0.0°table — no meets

Schedule adapted from the US Faceters Guild's Standard Round Brilliant. Full version at usfacetersguild.org.

02 / Round

Tolkowsky
Ideal #

Marcel Tolkowsky's 1919 proportions for the round brilliant — the math that defined "ideal cut" for a century. Pavilion 40.75°, crown 34.5°, table 53%. Same 58-facet arrangement as the Standard Round Brilliant; only the angles change.

Facets
58 + girdle
Table
53%
Pavilion angle
40.75°
Crown angle
34.5°
Total depth
59.3%
Published
1919 · public domain
Tolkowsky's numbers were computed for diamond (RI 2.42). For colored stones, keep his proportions but nudge the pavilion mains a few degrees above your material's critical angle — the same rule as always.
Cutting schedule

Pavilion

P140.75°96 12 24 36 48 60 72 84 · 8 mains
P2~42°03 09 15 21 27 33 39 45 51 57 63 69 75 81 87 93 · 16 lower-girdle facets
G90.0°girdle

Crown

C134.5°96 12 24 36 48 60 72 84 · 8 bezels
C2~26°06 18 30 42 54 66 78 90 · 8 stars
C3~18°03 09 15 21 27 33 39 45 51 57 63 69 75 81 87 93 · 16 upper-girdle facets
T0.0°table · 53%

Proportions from Marcel Tolkowsky's Diamond Design (1919), long in the public domain.

03 / Rectangle

Classic
Emerald Cut #

The step cut — long parallel facets like a staircase, flashing in broad planes instead of sparkle. Cut corners, a big open table, and a keel (a ridge, not a point) on the pavilion. It hides nothing, so cut it in clean rough.

Facets
49–57 typical
Table
60–65%
Pavilion
~40–43° steps
Crown
~30–35° steps
Length : width
1.30–1.50
Culet
Keel (ridge)
Step cuts are cut in rows: each pavilion step is a straight facet running the length of the stone, steepening toward the keel. Crown steps mirror them toward the table. Meet points matter less than straight, even rows — keep each step flat and parallel.
How to cut it

Pavilion

P1~43°keel line down the long axis — the two center rows meet here
P2~41°next step out, parallel to the keel
P3~39°outer step, meets the girdle
G90.0°girdle — rectangle with cut corners

Crown

C1~35°outer step, meets the girdle
C2~32°middle step
C3~28°inner step, meets the table
T0.0°table · 60–65%

The emerald step cut dates to the 1500s — long public domain. For full indexed diagrams, see the links below.

04 / Square

Fasscher
"Fake Asscher" #

Allan Aoyama's simplified Asscher-style square step cut — the Asscher look without the deep, complicated step pavilion. 4-fold mirror symmetry on a 96 index. Cuts quickly; the large pavilion facets can be a bear to polish.

Facets
41 (33 + 8 girdle)
Table
~38%
Symmetry
4-fold, mirror image
Index
96
RI
1.62 (adjust for your material)
L/W
1.00
BOG-optimized for tourmaline. Good for flat tourmaline sections — you can vary the step width of the crown to adjust for lack of material.
How to cut it

Pavilion

P139.60°96 · 24 · 48 · 72
P237.63°12 · 36 · 60 · 84
G90.00°girdle — 96 · 24 · 48 · 72 and 12 · 36 · 60 · 84

Crown

C141.00°96 · 24 · 48 · 72 and 12 · 36 · 60 · 84
C236.11°96 · 24 · 48 · 72 and 12 · 36 · 60 · 84
C331.33°96 · 24 · 48 · 72 and 12 · 36 · 60 · 84
T0.00°table

Design by Allan Aoyama (2011), shared free at omnifaceter.net.