Guide To Diamond Cuts

Diamond cuts and shapes explained

It is common to see the terms ‘cut’ and ‘shape’ used interchangeably to describe diamonds, even among some jewellers, though technically they refer to different aspects of a stone. The cut of a diamond is what gives it its unique and charismatic sparkle, and often this is more important to a stone’s looks than its clarity.

A diamond’s shape refers to the overall outline of the stone when viewed from the top, while the cut describes the facets, proportions, and reflective qualities the stone possesses. This might seem like an arbitrary difference, but it is important to be specific when discussing diamond jewellery as the terms for these properties often cause confusion.

Diamond cut is one of the four Cs of diamond quality grading, as mentioned previously it doesn’t refer to the shape, but rather the gem’s form in three dimensions. It looks at how symmetrical the diamond is, as well as the overall polished finish of the stone. The cut, rather than the shape, determines how light will travel through a diamond and how much of it will be reflected upwards to give it its sparkle.

The cut of a diamond is assessed by looking at the following factors:

  • Brilliance. A diamond’s brilliance refers to the way internal and external light is reflected
  • Fire. Diamonds refract light, and a precise cut will cause the diamond to emit bright flashes of colour across the visible spectrum
  • Scintillation. Scintillation refers to how light is reflected with movement, and the pattern of light and dark areas within a diamond caused by light reflections inside the stone

Timeless diamond shapes

Diamonds can take a variety of shapes and each is uniquely beautiful. A diamond’s shape is often one of the first things we notice aside from its brilliant shine. While round diamonds are some of the most popular and account for more than half of all diamond sales, there are plenty of other shapes to choose from. Each diamond shape has a standard measurement which ensures the proportions will always be as close to perfect as possible.

Round diamonds

Considered the classic diamond shape for engagement rings, this enduring shape is always fashionable and desired. The round diamond is unbeatable for its brilliant sparkle, and this is because the geometry of round diamonds allows for the reflection of light to be maximised more easily. A timeless choice, it is a popular shape for rings, earrings, necklaces and bangles. 

Pear diamonds

Also called a teardrop, pear shaped diamonds combine the brilliance of round diamonds with the sleek angles of marquise stones. To look their best, pear shaped diamonds should have an excellent or very good rating for their symmetry. Pear diamonds are often cut more shallowly than others so have a large surface area relative to their carat weight. 

Marquise diamonds

The marquise diamond is pointed on both ends with an elongated form, giving it a contemporary look. This shape is especially flattering for rings and its length gives it the illusion of being bigger than it is. Dramatic and beautiful, marquise diamonds originated in the 1700s and make striking solitaires or centrepieces for other stones.

Princess diamonds

The princess diamond is modern and edgy, featuring crisp angles and a huge amount of sparkle. They have a square silhouette and a shallow crown, giving the stone a commanding presence. A princess diamond has a lot in common with round shaped diamonds as they are technically a square brilliant cut stone.

Asscher diamonds

Asscher diamonds were a staple of the art deco era. They resemble emerald cut stones in many ways, though emerald shaped stones produce reflected light in bars while asscher diamonds have a spiralling windmill pattern. Emerald diamonds are usually rectangular in shape, though Asschers are more square and generally give much more brilliance and sparkle.

Trillion cut diamonds

These three sided diamonds are more uncommon than most shapes, but they are popular in luxury contemporary jewellery. Trillion shaped diamonds are attention-grabbing and make stunning accent stones or solitaires. The length of trillion diamonds’ sides gives the stone the impression of size, and when used as the main stone in a piece of jewellery the sides of the stone are often curved to make it look larger. 

Baguette diamonds

Another diamond that is commonly used as an accent stone is the baguette diamond. These are usually longer than they are wide. While similar to emerald shaped diamonds, baguettes have perfectly square corners and they do tend to be more long and narrow than emerald shaped stones. They usually have fewer facets than rounder shapes, giving them a less glittering look.

What is a triple X diamond?

Diamonds are graded in terms of their cut, symmetry and polish, and the maximum score they can receive is ‘excellent’. When a stone is graded as excellent across these three characteristics then it can be considered as having a triple X cut.

A skilled jeweller will be able to maximise on these three characteristics to produce cut diamonds of a superior quality. A high degree of craftsmanship is needed to ensure that each diamond is maximised in terms of its natural beauty and glimmer.

When stones score poorly in these three assessment categories they are likely to be dull and cloudy in appearance. They will not have the same brilliance and fire as a well cut stone and so are avoided in jewellery making. 

How do cut and shape affect a diamond's value?

Essentially, a diamond’s shape has little to no impact on its value though the quality of the cut does. Symmetry is possibly one of the most important factors when it comes to a diamond’s cost and the more perfectly aligned the cut is the more expensive the stone will be. A stone’s cost per carat dramatically increases as the quality of the cut increases, so triple X diamonds can generally be expected to cost the most per carat. 

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