Diamond brilliance: what it is and how cut affects it
Diamond brilliance is the white light a polished diamond returns to the eye, reflected off its surface and from inside the stone. It depends mostly on the cut: well-proportioned facets send light entering the top back out of the top, while a stone cut too shallow or too deep leaks it through the bottom.
3D Jewelry Designer1 min read
Brilliance, fire and scintillation
Three effects make up what people call a diamond's sparkle. Brilliance, also called brightness, is the white light. Fire is the flashes of colour from dispersion, which splits white light into a spectrum. Scintillation is the flicker of bright and dark as the stone or viewer moves.
Where brilliance comes from
Diamond has a high refractive index: light bends sharply as it enters, and light inside the stone that strikes a facet at a slant reflects back in. The pavilion, the stone's lower part, acts as angled mirrors that send light back up through the crown. Cut the pavilion too shallow or too deep and light escapes through it instead, leaving a glassy window or a dark centre.
Brilliance in a 3D render
A render shows brilliance only if it refracts light through the stone's facets, as a real diamond does. Lighting matters too: a diamond returns only the light around it. The studio renders diamonds with real refraction, dispersion and fire, and gems have their own lighting environment, separate from the metals. On an embed's Appearance tab, you can tune diamond brilliance; the default matches the studio.
Test your own file in the free 3D jewellery renderer, or read how to render diamonds realistically.
Questions
Do lab-grown diamonds have the same brilliance?
Yes, when cut to the same proportions. Lab-grown and mined diamonds are the same material, with the same refractive index.
Related
- Dispersion (fire) in diamonds and gemstones
Dispersion is how a gem splits white light into spectral colours, and fire is the flashes of colour you see. How it is measured and how it renders in 3D.
- Refractive index: how diamonds and gems bend light
Refractive index measures how strongly a gemstone bends light. What diamond's index of about 2.42 does for brilliance, and how a 3D render uses it.
- How to render diamonds realistically
A diamond render looks real when the stone refracts at diamond's index, light bounces inside it, dispersion adds fire and the lighting has contrast.