The hexagon cut is a fancy-shape gemstone cut defined by a six-sided polygonal outline, which may be regular — all sides and interior angles equal — or elongated along one axis to produce a more rectangular silhouette. The shape accommodates two principal facet architectures: the step cut, in which concentric rows of rectangular or trapezoidal facets run parallel to the girdle, and the brilliant cut, in which triangular and kite-shaped facets radiate outward from a central table. A hybrid arrangement, sometimes called a mixed-cut hexagon, combines step-cut crown facets with a brilliant-cut pavilion, or vice versa. The hexagon cut is particularly favoured for coloured gemstones — sapphires, emeralds, aquamarines, and tourmalines among the most common — where its geometric clarity both complements saturated colour and aligns with contemporary design sensibilities.

Geometry and Proportions

A regular hexagon is a highly efficient shape for a lapidary to cut from a hexagonal crystal system, since many gem minerals — including beryl, corundum, and tourmaline — grow with natural hexagonal cross-sections. This crystallographic correspondence means that a skilled cutter can orient a regular hexagonal outline to minimise waste from the rough, a practical consideration that has long made the shape attractive to cutters working with expensive material. In a regular hexagon, each interior angle measures 120 degrees, and the ratio of the short diagonal (the distance between two parallel sides) to the long diagonal (vertex to opposite vertex) is approximately 0.866. Elongated hexagons deviate from this ratio, typically stretching the stone along the axis connecting two opposite vertices to achieve a length-to-width ratio of 1.2:1 to 1.5:1, lending the outline a more finger-flattering appearance in rings.

The six corners of the hexagon present a structural consideration: sharp re-entrant angles are absent (unlike the pointed tips of a marquise or pear), but the six vertices are still susceptible to chipping, particularly in stones with pronounced cleavage such as topaz. Cutters routinely blunt or slightly round the corners to improve durability without materially altering the visual outline.

Step-Cut Hexagons

The step-cut hexagon is the more architecturally severe of the two principal styles. Facets are arranged in parallel rows — typically two to four on the crown and two to four on the pavilion — each row running parallel to one of the six sides of the girdle. The table is a flat hexagonal facet, and the culet, if present, may be a small hexagonal or point culet. Because step-cut facets act as large, open windows into the stone, this arrangement is unforgiving of inclusions and colour zoning, but it rewards stones of high clarity and strong, even saturation with a distinctive hall-of-mirrors depth. Step-cut hexagons in blue sapphire and in emerald are particularly striking: the geometry reinforces the stone's colour rather than breaking it into the scintillating flashes characteristic of brilliant cutting.

Brilliant-Cut Hexagons

A brilliant-cut hexagon replaces the parallel rows of step facets with a pattern of triangular and kite-shaped facets that radiate from the table toward the girdle, analogous in principle to the facet arrangement of a round brilliant but adapted to a six-fold symmetry axis. The result is a stone with considerably more light return and scintillation than its step-cut counterpart. Some cutters design brilliant hexagons with a central six-rayed star pattern visible through the table — an effect that echoes the asterism of a star sapphire without requiring a cabochon cut. Brilliant hexagons are less common in commercial production than step-cut versions, partly because the facet layout demands more precise planning and partly because the step-cut aesthetic has proven more enduring in fine jewellery design.

Historical and Design Context

Geometric fancy shapes, including the hexagon, gained significant traction during the Art Deco period of the 1920s and 1930s, when architects and jewellers alike embraced angular, symmetrical forms derived from modernist and machine-age aesthetics. Hexagonal stones appeared in platinum and white-gold settings of the period, often flanked by baguette or triangular diamonds in compositions that emphasised rectilinear precision. The shape experienced renewed interest during the mid-twentieth century Scandinavian modernist movement in jewellery design, and again in the early twenty-first century as a broader appetite for non-round engagement-ring stones — driven partly by social-media visibility of unconventional cuts — brought hexagons, kites, shields, and other geometric shapes into mainstream fine jewellery.

Contemporary designers frequently pair hexagonal coloured stones with yellow or rose gold settings that echo the warm tones of the metal against deeply saturated sapphires or parti-coloured tourmalines. The hexagon's six-fold symmetry also resonates symbolically with honeycomb imagery, and several jewellery houses have built collections explicitly around this motif.

Cutting Considerations and Trade Factors

Because the hexagon cut is not standardised in the way that the round brilliant is — there is no universally accepted ideal proportion table analogous to the Tolkowsky parameters — quality assessment relies heavily on the cutter's judgement and the buyer's visual evaluation. Key factors include:

• Symmetry: Opposite sides should be parallel and equal in length; the table should be centred; facet junctions should meet cleanly at their intended points.
• Windowing: In step-cut hexagons, an overly shallow pavilion produces a transparent window through the centre of the stone, reducing colour intensity. A well-proportioned pavilion angle — typically between 40 and 45 degrees for most coloured stones — avoids this.
• Extinction: Conversely, too steep a pavilion introduces dark extinction zones. The cutter must balance these competing demands against the optical properties of the specific material.
• Corner treatment: Slightly bevelled or rounded corners are preferable in stones with good cleavage; in tougher materials such as corundum, sharper corners are acceptable.

Hexagon cuts are produced both by hand in traditional lapidary workshops — particularly in cutting centres such as Jaipur, Bangkok, and Idar-Oberstein — and by computer-controlled faceting machines that can execute complex geometric patterns with high repeatability. Calibrated hexagons in standard millimetre sizes are available for use in mass-produced jewellery settings, though the shape is less universally calibrated than ovals or cushions, meaning bespoke settings are more often required.

Gemological Identification Notes

The hexagon cut does not alter the fundamental gemological properties of a stone — refractive index, specific gravity, spectral absorption, and inclusions remain unchanged by the choice of outline. However, the step-cut facet arrangement can make certain optical phenomena more visible during examination: colour zoning in corundum, for example, may be more apparent through the large open facets of a step-cut hexagon than through the complex facet pattern of a brilliant. Gemmologists examining hexagonal stones should rotate the stone under the microscope to assess zoning, and should evaluate the pavilion depth carefully when estimating the contribution of cut quality to apparent colour saturation.

Further Reading

• GIA Gems & Gemology — Fancy-Cut Coloured Stones
• International Gem Society — Fancy Cuts