For the most light, the round brilliant is the best cut for amethyst in our ray traces. It returns the most light of the ten classic shapes: brilliance 72 out of 100. The cushion (69) and the trilliant (63) come next. Of the ten shapes in amethyst, the oval scores highest for fire: 69, the round brilliant 36.
| Shape | Brilliance | Fire | Scintillation |
|---|---|---|---|
| Round brilliant | 72 | 36 | 80 |
| Cushion | 69 | 24 | 85 |
| Trilliant | 63 | 34 | 79 |
| Asscher | 60 | 52 | 72 |
| Emerald cut | 53 | 32 | 72 |
| Oval | 52 | 69 | 87 |
| Pear | 52 | 60 | 76 |
| Princess | 45 | 25 | 78 |
| Marquise | 38 | 48 | 86 |
| Radiant | 20 | 41 | 74 |
Why
Quartz, the species of amethyst, has the lowest refractive index of the seven stones we measure. So light escapes from it more easily than from the other six stones. Its dispersion is low, so its fire is faint to the eye.
Citrine and the other quartz gems share these optical properties, so these figures are a good guide for them too.
Of all 37 cuts we measure in amethyst, our own DG-M5 returns the most light: brilliance 85.
Compare any two cuts in the Cut Performance Wheel, or turn them in light in the 3D Gemstone Simulator.