Diamond cut describes how facets, proportions, polish and symmetry work together to manage light.

No. Shape is the outline; cut quality is the workmanship and light performance.

Cut strongly influences brightness, fire, scintillation, contrast and how lively a diamond appears.

The return of white light from a diamond to the viewer.

The separation of white light into spectral colors.

The flashes and contrast seen as the diamond, light or viewer moves.

IGI assesses polish, symmetry, proportions and light performance for round brilliant diamonds.

It is IGI’s current top overall cut grade for qualifying round brilliant diamonds.

It commonly refers to Excellent grades for cut, polish and symmetry on a round brilliant report.

No. Hearts & Arrows refers to optical symmetry seen through a special viewer.

A precise optical pattern visible in some highly symmetrical round brilliant diamonds.

No. Overall proportions, contrast, light performance, color and clarity still matter.

The width of the table facet relative to the diamond’s average width.

The total depth relative to the diamond’s average width.

The inclination of the upper main facets; it influences fire and light behavior.

The inclination of the lower main facets; it has a major effect on light return.

Yes. Excessive depth can hide weight, reduce face-up spread and affect light performance.

Yes. Overly shallow proportions can cause light leakage and weak contrast.

A bow-shaped dark contrast pattern that may appear in elongated fancy shapes.

No. Some contrast adds character, but a very dark bow-tie may be distracting.

Cut assessment differs by shape and laboratory; fancy shapes need shape-specific evaluation.

Check outline symmetry, brightness, bow-tie, length-to-width ratio, depth and spread.

Prioritize step alignment, flashes, symmetry, clarity appearance and windowing.

Compare brightness, facet pattern, bow-tie, depth and outline.

Compare facet style, symmetry, brightness, depth and spread.

Check symmetry, shoulders, tip alignment, bow-tie and point protection.

Check symmetry, bow-tie, length-to-width ratio and protection of both points.

Look for lively brightness, balanced chevrons, appropriate depth and corner protection.

Look for centered steps, windmill reflections, symmetry, clarity and spread.

For many buyers, prioritizing cut before chasing the highest color grade gives a stronger visual result.

Once a diamond is eye-clean and durable, extra budget often has more visible impact in cut, size or design.

Yes. Lab grown diamonds can achieve high cut, polish and symmetry grades.

Yes. Matched light performance helps earrings look balanced and lively.

Yes. A well-cut pendant or tennis necklace stays bright across normal lighting and movement.

Yes. Consistent matching and cut quality help the line of diamonds look even and bright.

Yes. Small diamonds still benefit from good matching, symmetry and secure setting.

Choose the shape you love, then prioritize strong light performance within that shape.

Yes. Prongs, bezels, halos, metal color and setting height can change contrast and visibility.

View diamonds in multiple lighting environments, rotate them and compare brightness and dark areas.

Yes, especially for fancy shapes, but they should supplement reports, measurements and in-person comparison.

Visit Sphere Diamond at CentralWorld Bangkok to compare shapes, cut quality, IGI reports and settings.

Yes, for qualifying stones and selected designs; confirm the report for the exact piece.

Choose the strongest light performance you can within your preferred shape, then optimize color, clarity and carat.