Three Different Kinds of Sparkle

Brilliance refers to the white light a diamond returns to the viewer. It is influenced by facet angles, proportions, symmetry, transparency, and the lighting environment. A bright diamond does not look uniformly white; it contains a useful pattern of bright and dark areas that gives the facets definition.

Diffuse lighting, such as light from a broad window or a softly lit room, is useful for comparing overall brightness. Look for a stone that remains lively across much of its face rather than one with a persistent dull center, washed-out area, or one side that repeatedly appears weaker.

Fire is the visible separation of white light into spectral colors. Small, directional light sources often reveal fire more clearly than broad diffuse light. This is why a diamond may show strong rainbow flashes beneath restaurant lighting yet appear mostly white near a large window.

More fire is not automatically better in every context. Facet size, pattern, and lighting determine whether the colored flashes appear broad and dramatic or small and numerous. The wearer may prefer one effect over another.

Scintillation is the pattern of bright flashes and dark contrast that changes as the diamond, observer, or light source moves. It includes both the number and distribution of flashes and the quality of the contrast pattern. A stone with balanced scintillation tends to look active rather than flat.

Movement is essential for evaluation. A still photograph freezes one moment and can overstate or hide dark zones. Slowly rock the diamond, then move it at normal hand speed. Observe whether flashes occur across the whole face or only near the edges.

Round brilliant diamonds are evaluated with a well-developed cut-grading framework, but fancy shapes create different optical signatures. An emerald shape uses broad step facets and often shows larger flashes. A princess cut creates geometric scintillation. Cushion and radiant shapes can range from broad to highly fragmented patterns.

• Round brilliant: Often an even balance of brightness, fire, and scintillation when well cut.
• Emerald and Asscher styles: Broad flashes and dramatic contrast rather than constant glitter.
• Princess: Angular, quadrant-based pattern with lively brilliant-style reflections.
• Cushion and radiant: Highly variable; compare actual facet pattern and motion.
• Oval, pear, and marquise: Check the center for a bow-tie that either adds contrast or becomes persistently dark.

Bright spotlights can make almost any clean, faceted surface look lively. Conversely, flat office lighting can make a beautiful stone look less dramatic. Compare diamonds under at least two environments: broad neutral light and smaller directional light. Also shade the stone briefly from overhead reflections to see whether brightness remains balanced.

Phone cameras apply exposure, sharpening, white balance, and compression. Use videos to identify patterns and compare shape, but do not treat a screen as a complete substitute for a consistent side-by-side viewing method.

1. Place the diamonds in the same orientation and lighting.
2. Compare overall white brightness face up.
3. Rock each stone slowly and watch whether dark zones move or remain fixed.
4. Move the stones at normal hand speed to judge scintillation.
5. Use a smaller light source to compare fire.
6. Step back to normal viewing distance before making a preference decision.
7. Review the grading information only after noting what you actually see.