A mixed cut is any faceting design that combines brilliant-cut and step-cut elements on the same stone. The most common configuration features a brilliant-cut crown over a step-cut pavilion, but the reverse arrangement and a number of more elaborate combinations are also encountered. Mixed cuts are widely used in coloured-stone cutting where the requirements of weight retention, colour distribution, and brilliance are traded off against one another in ways that pure brilliant or pure step designs do not always serve well.

The two parent styles

Brilliant cuts arrange faceting in radial patterns around the stone's central axis, with triangular and kite-shaped facets that maximise light return through dispersion and total internal reflection. The round brilliant for diamonds is the canonical example. Step cuts arrange faceting in parallel rows of rectangular facets stepping down from the table to the culet, with the emerald cut as the classic example. Step cuts emphasise the colour and clarity of the stone over the dispersion-driven brilliance that defines brilliant cuts.

Why mixed cuts are used

The mixed-cut format is used for several reasons. Weight retention from the rough crystal is sometimes optimised by a mixed configuration that respects the natural shape of the rough better than either pure style alone. Colour distribution in stones with strong colour zoning can be managed by mixed cutting that places the strong colour at the pavilion (where it shows through the table) while the crown is cut for additional optical effect. Brilliance can be enhanced over a pure step cut for stones where some return of dispersed light is desirable.

The Ceylon cut, common in Sri Lankan sapphires, is one widely encountered mixed-cut variant: a brilliant-style crown over a step-style pavilion, with the crown cut to maximise life and brilliance and the pavilion cut to retain weight and to manage the colour. The Barion cut, developed by Basil Watermeyer in South Africa, is a more recent mixed-cut design that combines brilliant-cut crown facets with a modified pavilion design and crossed pavilion girdle facets.

In the coloured-stone trade

Mixed cuts dominate the commercial coloured-stone trade. Most cushion-cut sapphires, oval-cut rubies, and antique-cushion-style stones are mixed cuts of one variety or another. The flexibility of the format allows the cutter to optimise individual stones rather than forcing a fixed faceting template. The trade-off is that mixed cuts are less standardised than brilliant or step cuts and consequently less amenable to the kind of cut-grade analysis that GIA applies to round-brilliant diamonds.

In diamond cutting

Mixed cuts in diamond are increasingly seen in fancy-shape diamonds and in fancy-coloured diamonds, where weight retention and colour management are higher priorities than for colourless round brilliants. The format is documented on GIA grading reports under the cut description, with the specific arrangement noted.

In the trade

Skyjems regularly handles mixed-cut coloured stones in cushion, oval, and antique-cushion shapes. Buyers should evaluate mixed-cut stones on the same criteria as any other cut: how well the cut returns light, how the colour reads, how the stone faces up, and how it performs across viewing angles. The cut style itself is neutral; the execution within the style is what matters.

Further reading

• GIA Gems & Gemology — coloured stone cut and faceting articles
• International Gem Society — gem cutting styles