Scintillation
The flashes of light and the pattern of light and dark areas seen in a gemstone when it, the light or the viewer moves.
Two parts of sparkle
Gemologists describe scintillation as two things. The first is the flashes, the on and off sparkle as facets catch and lose the light. The second is the pattern, the arrangement of bright and dark areas across the face of the stone. A good pattern is balanced and crisp, while a poor one shows large dark patches or a washed out face.
What controls it
Facet arrangement and size change scintillation. Large facets, as in step cuts, give broad flashes. Many small facets, as in brilliant cuts, give a busier, pinpoint sparkle. Lighting matters as much as the cut, because sparkle needs several light sources and contrast around the stone.
Rendering and presenting scintillation
A still image can only freeze one moment of scintillation, which is why jewelers rely on video. A slow turntable or 360° clip lets buyers watch the flashes travel across the stone. Keep the rotation slow so the eye can follow the sparkle, and use a gem environment with several distinct light sources.
In the RenderMyJewels studio, the turntable and 360° video export are built for this. Export the same clip in square for product pages and in 9:16 for reels and stories, then convert the WebM file to MP4 with any free converter if a platform needs it. Avoid heavy bloom, which smears pinpoint flashes into a glow and hides the very effect you want to show.