Process
A cut design is a set of measurements, not an adjective.
Most faceting decisions get made by eye, against a render, or by copying a design that worked well in a different material. We verify geometry with the same ray-tracing approach used to engineer optics generally — before a single facet touches a cutting wheel — so the numbers we quote you are numbers you can check.
Why a pretty render isn’t a verified cut
A rendered preview shows you one lighting setup, one camera angle, one moment. It doesn’t tell you whether the design holds its brightness as the stone tilts on a finger, whether the pavilion angles sit safely above the material’s critical angle, or whether the “window” — the see-through dead zone at the center of a poorly cut stone — is 3% of the face or 15% of it. Those are measurements, and measurements are what we design against.
The pipeline
Six steps between a candidate shape and a cuttable spec.
Candidate sourcing
We start from a wide pool of candidate geometries — historical faceting designs and original studio work — rather than committing to one shape early and hoping it performs.
Index-specific ray tracing
Every candidate is re-traced at the target species' own refractive index, not the index it was originally designed for. A design that's safe in one material isn't automatically safe in another — sapphire and diamond bend light differently, and the geometry has to be re-checked, not assumed.
Optical scoring
Each candidate is scored on ISO brightness, window fraction (how much of the face reads as a flat see-through patch versus faceted fire), and pavilion margin — how far the critical facet angles sit above the material's critical angle, in degrees.
Tilt-tolerance stress test
A cut that only performs at one exact viewing angle is a cut that under-performs on a jeweler's bench. We sweep tilt across a working range and report the tolerance in degrees, so the number describes real handling, not a single hero screenshot.
Cross-verification and re-angling
When a promising design wasn't originally written for the target material, we re-angle it facet by facet and re-run the full scoring pass. Eye of Zul is the proof case: a design that needed real intervention to become cuttable, kept and verified rather than discarded.
Cutting-diagram handoff
The verified geometry — facet angles, index positions, tolerance bands — goes to master cutters as a cutting diagram, not a mood board. What gets cut is what got verified.
What this means for your line
Retailers and brands buying loose stones are exposed when a cut’s performance is inconsistent from stone to stone, or when a supplier can’t explain why one cut looks brighter than another. Verified geometry gives you a specification to buy against — the same one, every time — and a vocabulary (window fraction, pavilion margin, tilt tolerance) you can put in front of your own customers.
Every signature cut and every reference cut in the Gem Library carries its own spec sheet with these numbers attached.
Want the full methodology walked through on a call?
We’re happy to go line-by-line through a cut sheet with your team.