The hexagon brilliant is a modified brilliant cut in which the girdle outline forms a regular or near-regular hexagon while the crown and pavilion retain the triangular and kite-shaped facets characteristic of brilliant-cut geometry. Rather than abandoning the optical logic of the round brilliant in favour of a purely decorative silhouette, the hexagon brilliant adapts that logic to a six-fold symmetry, preserving strong light return and internal scintillation within a distinctly geometric frame. It is applied to both diamonds and coloured gemstones, and occupies a position between the purely architectural step cuts — such as the emerald or Asscher — and the optically aggressive round brilliant.

Geometry and Facet Architecture

The defining characteristic of any brilliant cut is the arrangement of facets in radiating, triangular or kite-shaped groups that direct light from the pavilion back through the crown toward the viewer. In a round brilliant, this arrangement is organised around eight-fold symmetry; in the hexagon brilliant, it is reorganised around six-fold symmetry, matching the six sides of the girdle outline.

The crown typically comprises a table facet, six kite-shaped bezel (or main) facets aligned with the six corners of the hexagon, and a series of triangular star and upper girdle facets filling the spaces between them. The pavilion mirrors this arrangement with six main facets and corresponding lower girdle facets converging toward a culet. The precise facet count varies by cutter and house style: some interpretations are relatively simple, with a modest girdle facet count; others, particularly in high-end diamond cutting, multiply the girdle facets to increase scintillation and soften the visual transition between the flat sides of the outline.

The regularity of a true hexagon — all six sides equal, all interior angles 120 degrees — means the outline is geometrically close to a circle, which is optically advantageous. The deviation from circularity is smaller than in a square or rectangular brilliant, so the pavilion facet angles required to achieve total internal reflection can remain close to those used in round brilliant cutting. This makes the hexagon brilliant more forgiving to cut for light performance than, say, a triangular brilliant, where the acute corners impose greater optical compromises.

Proportions and Light Performance

No single industry standard governs hexagon brilliant proportions in the way that GIA and AGS grading reports codify round brilliant cut quality. Cutters and manufacturers therefore exercise considerable latitude. As a general principle, table percentages in the range of 55–65 per cent of the longest diameter, crown angles of approximately 33–36 degrees, and pavilion angles of 40–43 degrees are considered conducive to strong brilliance. Deviations toward shallower pavilions produce a washed-out, glassy appearance; excessively deep pavilions produce a dark, windowed centre.

Because the six corners of the hexagon are less acute than those of a triangular or square brilliant, light leakage at the corners is less severe. Nevertheless, the flat sides of the hexagon — unlike the continuously curved girdle of a round brilliant — can produce localised zones of reduced brilliance if the adjacent facets are not precisely angled. Skilled cutters compensate by adjusting the lower girdle facet angles along the flat-side sections of the girdle.

Applications in Diamonds

The hexagon brilliant has attracted renewed interest in the diamond trade as part of a broader movement toward geometric and non-round shapes that began gaining momentum in the 2010s. It appeals to buyers who want the optical liveliness of a brilliant cut but prefer a silhouette that reads as deliberately architectural rather than traditionally round or oval. In diamond jewellery, hexagon brilliants appear as solitaire centre stones, as side stones flanking larger rounds or ovals, and in pavé or channel arrangements where their flat sides allow tight, honeycomb-like setting patterns.

The honeycomb association is not incidental: the hexagon's ability to tile a plane without gaps makes it uniquely suited to multi-stone pavé layouts in which adjacent stones share girdle edges, a configuration sometimes called a honeycomb pavé. This geometric efficiency is one of the hexagon brilliant's most practical advantages over other non-round shapes.

Applications in Coloured Gemstones

In coloured stone cutting, the hexagon brilliant is used when a cutter or designer wishes to retain the colour saturation and light return of a brilliant cut while presenting a more geometric outline than a round or oval. Sapphires, spinels, tourmalines, and garnets are among the species most commonly encountered in this cut. For strongly pleochroic stones such as tanzanite or certain tourmalines, the hexagon brilliant offers the cutter a useful degree of flexibility: by orienting the table perpendicular to or parallel with the optic axis, the cutter can select which pleochroic colour dominates the face-up appearance, while the brilliant facet arrangement maximises the intensity of that colour.

The cut is also seen in synthetic and laboratory-grown stones, where the precision of modern faceting equipment makes the strict geometric regularity of a true hexagon easier to achieve than it would be in hand-cutting.

Historical and Design Context

Hexagonal outlines have appeared in gem cutting since at least the early twentieth century, when geometric forms associated with Art Deco design encouraged cutters to explore non-round silhouettes. However, the hexagon brilliant as a specifically brilliant-faceted variant — as opposed to a hexagonal step cut or a simple hexagonal cabochon — is largely a product of the late twentieth and early twenty-first centuries, enabled by computer-aided design tools and precision faceting equipment that allow cutters to model and execute complex facet arrangements with the accuracy that a six-fold brilliant requires.

The cut sits within a broader family of modified brilliants that includes the princess cut (square), the trillion or trilliant (triangular), the radiant cut (rectangular or square with cut corners), and the oval brilliant. Each represents an attempt to reconcile a non-circular outline with the optical demands of brilliant-cut facet geometry. The hexagon brilliant's close approximation to a circle gives it a natural optical advantage within this family.

Grading and Certification

As with most fancy-shape brilliants, no major laboratory has published a standardised cut-grade system for hexagon brilliants equivalent to GIA's round brilliant cut grade. Laboratories such as GIA, Gübelin, and SSEF will certify hexagon brilliant diamonds and coloured stones for colour, clarity, and carat weight, and will describe the cut style, but cut quality assessment remains largely at the discretion of the individual cutter, dealer, or buyer. Purchasers evaluating hexagon brilliants for light performance are advised to examine stones under a variety of lighting conditions — diffuse overhead lighting, spot lighting, and natural daylight — and to look for even distribution of brightness across all six sections of the stone, with no pronounced dark or washed-out zones at the flat sides or corners.

In the Trade

Hexagon brilliants are produced in relatively modest volumes compared with round brilliants, ovals, or cushions, and are therefore considered a specialty cut. They command a modest premium over standard round brilliants of equivalent weight in coloured stones when the cut is well executed, though in diamonds the premium is less consistent and depends heavily on the individual stone's light performance and the current market appetite for geometric shapes. Dealers and designers working with hexagon brilliants frequently emphasise the cut's versatility in both solitaire and multi-stone settings, and its visual compatibility with contemporary architectural jewellery design.