Gemstone Cuts

The process of transforming a rough precious stone into the beautiful, sparkling stones that are set into jewellery is a multi-stage process. Long before a jeweller begins their work in mounting and securing the stones to precious metals so they can be worn, skilled professional gem cutters known as “Lapidaries” cut the stone into increasingly complicated forms.

The lapidary who first examines the rough diamond will check the stone carefully to identify any flaws and imperfections. Where other minerals have become trapped within the stone they form what are known as “inclusions”. When the lapidary is making their first cuts they attempt to preserve the maximum amount of size (measured in carats) whilst cleaving, cutting or grinding away any large flaws.

Successive lapidaries will then calculate the angles required to form the diamond’s final shape. Here they attempt to obscure any remaining flaws, maximise the amount of light that can flow through the stone, and create the most impressive final stone that they can.

Modern diamond cutting is mathematically calculated using computer simulations, but antique diamonds were all hand cut, taking a great deal of time and a steady hand as well as the practical knowledge that a modern lapidary must have.

Choice of Cut

Whilst there are certain diamond cuts that are more common than others they are by no means uniform. In many cases the shape of the rough will dictate the final shape that the diamond will take. This is particularly true of large stones, where a chief concern is preserving the mass of diamond present.

Below is a list of the most common cuts that can be found in antique jewellery. Modern lapidaries have taken advantage of new technology and increased scientific understanding to create a myriad of new shapes, however the following classic cuts can all be found in antique pieces.

BRILLIANT CUT 

Pioneered in the 18th century, the Brilliant Cut is the most prevalent cut in modern jewellery. Over the centuries since its invention the cut has been constantly refined and improved upon by successive generations of jewellers. The brilliant cut has 56 facets, excluding the table and culet, the latter of which is flattened in modern cuts. Modern brilliant cuts are machined perfectly, but as antique stones were cut by hand they are often not completely symmetrical. This is a key indicator that the piece is an antique rather than a modern imitation. Brilliant cuts are almost circular when viewed from above, in contrast to other, older cuts.

STEP CUT

These cuts are used for diamonds, but more commonly for coloured stones such as emeralds or rubies. They are either square or rectangular, with large straight facets running parallel to one another. Fragile corners are removed, so that the stones are more hardwearing and durable. One of the most recognisable step cuts is the Emerald Cut, so named because it is mainly used with these stones. Emerald are particularly rare, valuable and fragile so every care is taken to ensure that they can survive once cut to shape. Diamonds, which are much tougher, are able to take more elaborate shapes and remain strong. Another variant of step cut is the ‘baguette’ cut.

Sometimes known simply as “old cut” this shape was the forerunner of the modern brilliant cut, and was particularly prevalent during the Georgian, Victorian and Edwardian eras. Where the modern brilliant cut has been formed to take advantage of electric light, the old cut predates this invention and was intended to make the most of candlelight. Larger facets mean that the fire within is softer and more subtle than a modern stone. Old cut diamonds dance by firelight, and have a lustre that many find more desirable than their modern counterparts.

This cut contains only 17 facets, and is less costly than the brilliant cut as a result. The shape allows retention of more mass than the brilliant cut, which makes it ideal for smaller diamonds (below around 2mm). The effect of an eight cut diamond can be easy to mistake for that of a brilliant cut with the naked eye, and it is only under magnification using a jewellers loupe that the difference can be determined.

OVAL BRILLIANT CUT

Regular brilliant cuts are circular when viewed from above, but lapidaries may choose to adopt a more elongated oval shape with particular stones. These cuts are often aligned in rings so that their longest point runs parallel to the finger, creating a more elegant, slimmer profile whilst maintaining the lustre of the brilliant cut’s many facets.

PEAR BRILLIANT CUT

Commonly known as a ‘drop” the pear cut is fashioned into a teardrop shape, usually placed in jewellery so that the droplet’s larger end flows downwards. The diamond’s incredible hardness allows the narrow edge of the pear cut to retain its shape without risking damage to the stone.

HEART BRILLIANT CUT

Heart cuts require a high degree of skill to fashion. The stone is cut into a stylised heart shape, and must be cut with extreme care to make the cleft well defined enough to stand out. Antique heart diamonds are cut without the aid of modern machinery, and the difficulty of doing so means that a high-quality specimen is highly desirable.

MARQUISE CUT

These diamonds are also known as ‘navette’ or boat-shaped. They are essentially a variant of the brilliant cut which have been used since the 18th century, where it was particularly popular in France, where it often formed the centrepiece of court jewellery. Whilst the cut became less popular in the 19th century, it has since enjoyed a resurgence, and can be found in many unique pieces, both antique and modern.

PRINCESS CUT

The Princess cut’s technical name is ‘square modified brilliant’. It was named the princess cut in the 1960s, but many precursors to the current form exist. Varieties of quadrillion and other square cuts were the precursors to the modern princess cut, although the name is often retroactively applied to antique pieces which meet the criteria.

CABOCHON CUT

Unlike any other cut described here, the cabochon cut has only a single flat surface, and is cut into a curved dome rising from this plane. The cabochon is particularly suited to translucent stones such as moonstone. It is most commonly used for opals to prevent the natural striations of colour from within being obscured by facets. It can also be used with heavily flawed stones which cannot survive, or would not benefit from, the faceting process.

CUSHION CUT

This cut, also known as the ‘mine cut’ is often thought of as a modern shape, chiefly because it is one of the most popular cuts to be used in diamond engagement rings. Its origin lies in the 19th century, where it was named after the Brazilian diamond mines which were providing large numbers of diamonds at the time. Cushion cuts have 64 facets, six more than the brilliant cut, and these extra facets create a more elaborate sparkling display in modern lights. Diamonds benefit from this cut, but it is also often used for sapphires and rubies.

ROSE CUT

These historic cuts originated in the 16th century, and represent a simpler but no less beautiful cut which has been popular for centuries. With 24 triangular facets at the top and a flat base, these are an economic way of cutting diamonds. They have been historically used with all manner of gemstones, but amongst the most common were garnets during the reign of Queen Victoria.

BRIOLETTE CUT

Like the pear cut, the briolette cut has one slim and one larger rounded end. Where the pear cut is a flattened teardrop the briolette is a fully three-dimensional teardrop. It is cut in the same fashion as the rose cut, with triangular facets, that give it a very distinctive look.

The Four C’s

When a jeweller is appraising the value of a diamond they will look at the stone’s cut as part of that process. It is one of the four C’s which determine the desirability and value of the stone, the others being Carat (weight), Clarity and Colour.

To learn more about the four Cs take a look at our article here.

If you have any questions about our stones, or about the cut of a particular piece’s stones, please do not hesitate to get in touch. Our dedicated team of experts will be happy to provide any information you require.