3D model · 74 facets · 9.06 x 7.06 mm
The radiant: the outline of a step cut, with cropped corners, and a brilliant facet plan. It combines the clean shape of an emerald cut with the sparkle of a brilliant.
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The radiant: the outline of a step cut, with cropped corners, and a brilliant facet plan. It combines the clean shape of an emerald cut with the sparkle of a brilliant.
A strong choice for colored stones, where the mixed facets help spread color evenly.
Measured from the delivered model, not quoted from a standard.
The Radiant Cut performs best in moissanite, where its brilliance and fire together are highest: 33 for brilliance and 92 for fire. In diamond it scores 32 for brilliance and 77 for fire, against 93 and 78 for the T73 benchmark. Its scintillation, 74, comes from its pattern of facets, so it is the same in every stone.
| Gemstone | Brilliance | Fire | Scintillation |
|---|---|---|---|
| Diamond | 32 (T73 benchmark 93) | 77 (T73 benchmark 78) | 74 (T73 benchmark 80) |
| Moissanite | 33 (T73 benchmark 86) | 92 (T73 benchmark 97) | 74 (T73 benchmark 80) |
| Cubic Zirconia | 33 (T73 benchmark 98) | 91 (T73 benchmark 87) | 74 (T73 benchmark 80) |
| Ruby | 26 (T73 benchmark 94) | 69 (T73 benchmark 37) | 74 (T73 benchmark 80) |
| Sapphire | 26 (T73 benchmark 94) | 69 (T73 benchmark 37) | 74 (T73 benchmark 80) |
| Emerald | 22 (T73 benchmark 78) | 56 (T73 benchmark 39) | 74 (T73 benchmark 80) |
| Amethyst | 20 (T73 benchmark 72) | 41 (T73 benchmark 36) | 74 (T73 benchmark 80) |
Brilliance is the share of face-up light that the stone returns. Fire is the share of that light that splits into color. Both come from our face-up light census. Scintillation is the sparkle that the facets give as the stone moves, and we read it from its facets. They are the same figures as the Cut Performance Wheel, where you can compare the Radiant Cut with any other cut. A simulation of the geometry, not a grading report.
The same geometry behaves differently in every material. Light that meets a pavilion facet at less than the critical angle of the stone does not reflect. It passes straight out of the back and shows face-up as a window. For each stone, we measured how much of the pavilion of this model, seen face-down, is steeper than that angle. We also measured what the model weighs at its reference size.
| Stone | Refractive index | Critical angle | Pavilion reflecting head-on light | Weight at this size | Verdict |
|---|---|---|---|---|---|
| Diamond | 2.417 | 24.4° | 96% | 2.00 ct | Minor windowing |
| Moissanite | 2.648 to 2.691 | 22.2° | 96% | 1.83 ct | Minor windowing |
| Cubic Zirconia | 2.15 to 2.18 | 27.7° | 96% | 3.30 ct | Minor windowing |
| Ruby | 1.762 to 1.770 | 34.6° | 38% | 2.27 ct | Steepen the pavilion |
| Sapphire | 1.762 to 1.770 | 34.6° | 38% | 2.27 ct | Steepen the pavilion |
| Emerald | 1.577 to 1.583 | 39.4° | 29% | 1.55 ct | Steepen the pavilion |
| Amethyst | 1.544 to 1.553 | 40.4° | 29% | 1.51 ct | Steepen the pavilion |
Head-on light, first reflection. The 3D Gemstone Simulator traces the full Light Return in each of these gemstones.
The Radiant Cut stone by stone: what each gemstone gains and loses in this cut, measured.
Open it in the 3D Gemstone Simulator. Set its carat, color, clarity and cut grade in any of seven gemstones. Turn it under ten kinds of light, and watch its 3D gemstone report change as you go. Free, in your browser.
Six formats. STEP is the exact faceted solid for CAD, and 3DM is for Rhino. STL and OBJ are meshes. FBX is for Blender, 3ds Max, Maya, Cinema 4D, Unity and Unreal. GLB is for the web and AR. All are in millimeters at real-world scale, with 74 planar facets.
The faceting design for the Radiant Cut is in preparation. It will contain a GemCad file, a tier table and a printable diagram. The 3D files are available now.
We measured the pavilion of this model against the critical angle of each stone. In none of the seven stones does the whole pavilion reflect head-on light. In Ruby, Sapphire, Emerald, Amethyst, part of the pavilion lets light out of the back, so we advise a steeper pavilion.
The cutting file for the Radiant Cut is in preparation. Before a cutting file goes on sale, we check it facet by facet against its 3D model.
The model measures 9.06 x 7.06 x 3.79 mm, which is 2.00 ct in diamond. At the same size, it weighs 1.83 ct in moissanite, 3.30 ct in cubic zirconia, 2.27 ct in ruby, 2.27 ct in sapphire, 1.55 ct in emerald, 1.51 ct in amethyst. You can scale it uniformly to any size: the weight follows the cube of the size.
Yes. The mesh is watertight and manifold, with outward normals and no duplicate vertices, so it prints and casts without repair. Use the STEP file when you need the exact faceted solid in CAD.
The Radiant Cut as exact geometry: 74 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The faceting design for the Radiant Cut is in preparation. It will include the GemCad file, the tier table and a printable diagram.
Save with a bundle: the Radiant Cut 3D files are also in Jewelry Essentials 3D, 10 cuts for €29.99 until 1 December, then €39.99 (€99.90 as single files). Buy the bundle.
Not sure the files open in your software? Get the cube free: the same six formats, for your email address, used only to send them (privacy).
Questions before you buy? Email us.