The cushion brilliant is a faceting style in which a cushion-shaped gemstone — characterised by its rounded corners and gently curved sides — carries a fully brilliant-style facet arrangement: a flat table, a crown composed of main and star facets, and a pavilion in which the principal mains radiate outward from a central culet point, typically four mains per quadrant. The result is a stone that combines the soft, pillow-like silhouette associated with antique and Georgian-era cutting with the optical dynamism of a modern brilliant, producing strong scintillation and well-defined light return. On GIA grading reports, the designation cushion brilliant is applied specifically when this arrangement is present, distinguishing it from the related but optically distinct cushion modified brilliant, which incorporates additional pavilion facets between the mains.

Historical Context

The cushion outline is among the oldest standardised gem shapes in the Western lapidary tradition. Throughout the seventeenth and eighteenth centuries, cutters working in Antwerp, Amsterdam, and later London produced what are now called old mine cuts — stones with a high crown, small table, large culet, and a cushion-like girdle outline that followed the natural octahedral rough. These early cuts were not brilliant cuts in the modern sense, but they established the cushion as the dominant shape for fine diamonds and coloured stones well into the nineteenth century. As mathematical understanding of light behaviour in faceted stones advanced, cutters refined the proportions and facet geometry, gradually producing what we now recognise as the cushion brilliant: a more systematic arrangement that retains the antique outline while achieving the light performance associated with the round brilliant.

The cushion brilliant thus occupies a historically resonant position in the lapidary canon. It is neither purely antique nor purely modern, but a considered synthesis — a shape that reads as classic and romantic while performing with contemporary optical efficiency.

Facet Architecture

In a standard cushion brilliant, the crown typically features a table facet, eight main (kite) facets, eight star facets, and sixteen upper girdle facets, arranged in a pattern directly analogous to the round brilliant crown. The pavilion carries eight main facets radiating from the culet — four per quadrant — together with sixteen lower girdle facets. This geometry is the defining characteristic of the cushion brilliant designation: the pavilion mains meet at or near a central point, creating the classic four-fold radial symmetry visible through the table as a distinctive pattern sometimes described informally as a "crushed ice" or "chunky" appearance, depending on proportions and the degree of optical contrast.

The precise angles of crown and pavilion, the depth percentage, and the table-to-girdle ratio all vary considerably among cutters and cutting centres. Unlike the round brilliant, no single set of ideal proportions has been universally codified for the cushion brilliant, and the shape's appeal is partly aesthetic — buyers and cutters make deliberate choices about the balance between brilliance (white light return), fire (chromatic dispersion), and scintillation (the flash of light and dark as the stone moves).

Cushion Brilliant versus Cushion Modified Brilliant

The distinction between the cushion brilliant and the cushion modified brilliant is precise and consequential for grading and trade purposes. GIA introduced the separate designation to reflect a meaningful difference in pavilion architecture. In the cushion modified brilliant, additional facets — often called extra facets or pavilion mains — are inserted between the primary pavilion mains, breaking the clean four-fold radial symmetry and producing a different visual texture. This modified arrangement is extremely common in the trade and is the configuration found in the majority of cushion-cut diamonds sold today.

The cushion modified brilliant tends to produce what many observers describe as a more fragmented, sparkling appearance — sometimes called the "crushed ice" look — because the additional facets create smaller, more numerous light reflections. The cushion brilliant, by contrast, produces larger, more defined light patches and a pattern that more closely resembles the optical behaviour of a round brilliant. Neither is inherently superior; the preference is a matter of aesthetic taste and, in coloured stones, of how the facet arrangement interacts with the gem's body colour and pleochroism.

On a GIA Diamond Grading Report or Coloured Stone Report, the shape and cutting style field will read either "Cushion Brilliant" or "Cushion Modified Brilliant" — a distinction that has become increasingly important to buyers and dealers who seek a specific optical character.

Cushion Brilliants in Coloured Stones

Among coloured gemstones, the cushion brilliant is one of the most widely used cutting styles. Sapphires — particularly those from Sri Lanka, Madagascar, and Kashmir — are frequently cut in cushion brilliant form, as the shape accommodates the hexagonal rough efficiently while the brilliant facet arrangement maximises colour saturation and light return. Many of the most celebrated sapphires in auction history, including large Ceylon and Burmese stones, are cushion brilliants or closely related antique cushion cuts.

Rubies, spinels, and chrysoberyls are also commonly encountered in cushion brilliant form. For strongly pleochroic stones such as tanzanite or alexandrite, the cutter's orientation of the rough relative to the optical axes is critical, and the cushion brilliant's facet geometry must be considered alongside the crystallographic orientation to achieve the desired face-up colour. In padparadscha sapphires and fine pink sapphires, the cushion brilliant is particularly favoured because the larger, more unified light patches it produces tend to show the body colour more evenly than the fragmented reflections of a modified brilliant.

Proportions and Quality Considerations

Because no universal ideal-cut standard exists for the cushion brilliant, quality assessment relies on a combination of measurable parameters and visual evaluation. Key considerations include:

• Depth percentage: Cushion brilliants cut for coloured stones are often deeper than their diamond counterparts, as depth is used to intensify colour saturation. Depths of 65–75% of the width are common in fine sapphires and rubies, whereas diamond cushion brilliants are more typically cut in the 60–68% range.
• Table percentage: A smaller table relative to the overall diameter tends to increase fire and give the stone a more antique character; a larger table increases brilliance and face-up size.
• Girdle outline: The curvature of the sides and the degree of rounding at the corners define the character of the cushion silhouette. More pronounced curves produce a rounder, softer look; straighter sides approach a square or rectangular outline.
• Symmetry: As with all brilliant cuts, symmetry of the facet arrangement — both in the outline and in the alignment of crown and pavilion facets — directly affects optical performance and is assessed on GIA reports.
• Windowing and extinction: Poorly proportioned cushion brilliants in coloured stones may exhibit a transparent "window" through the centre or excessive dark extinction, both of which reduce the apparent quality of the colour.

In the Trade

In the contemporary diamond trade, the cushion modified brilliant is significantly more prevalent than the cushion brilliant, largely because the modified arrangement is easier to achieve from certain rough shapes and because the crushed-ice aesthetic has been commercially dominant for much of the early twenty-first century. However, there has been a sustained and growing interest among collectors and designers in the cushion brilliant specifically, driven by a preference for the more structured, round-brilliant-like optical pattern it produces.

For coloured stones, the cushion brilliant remains the standard cutting style at most cutting centres in Sri Lanka, Thailand, and Madagascar. Dealers and gemmologists working with fine sapphires, rubies, and spinels will routinely encounter the cushion brilliant as the default shape, and the ability to assess its proportions, symmetry, and optical performance is a fundamental competency in coloured-stone trading.

When a GIA Coloured Stone Report specifies "Cushion Brilliant" as the cutting style, it provides meaningful information to the buyer about the pavilion architecture and the likely optical character of the stone — information that is not available from the shape designation alone and that can influence both aesthetic preference and, in some cases, value.

Further Reading

• GIA Gem Encyclopedia — gia.edu
• Gems & Gemology journal — gia.edu