Seven of the Rarest Diamond Cuts in the World

Ready to be discovered in-store 

The chances are you have never seen any of these diamonds before. They are so rare that even seasoned jewellers may never have held one, so new that most of the world are yet to encounter them. These are not the classics you are familiar with. These cuts that change what you know.

Here are seven of the most extraordinary ready for your custom design engagement ring: 

Oval Portuguese Cut

The Portuguese cut is already one of the most demanding facet arrangements ever devised.  Typically a Round Portuguese cut features 156 facets that produce truly spectacular fire. The Oval Portuguese cut takes that complexity and stretches it across an elongated form, and the effect is nothing short of breathtaking.

What makes it so rare is the sheer difficulty of execution. The cutter must maintain perfect symmetry across an asymmetric outline while preserving the precise angles that generate the cut's signature brilliance. A single miscalculation collapses the optical effect entirely. Today, only a handful of cutters in the world attempt it with any regularity, which means finding one in is genuinely uncommon. When you do, you're looking at something close to sculpture for exceptional jewellery.

Hexagon Step Cut

Step cuts with their parallel, stair-like facets forever prioritise clarity and colour over sparkle. The emerald cut is their most famous expression. The hexagon step cut belongs to the same family but trades the rectangle for six equal sides, and the result has a quietly mesmerising quality that rounds and brilliants simply cannot replicate.

Because step-cut facets are large and open, they act as mirrors rather than prisms. Light enters and reflects back in broad, white flashes. In a hexagon, those flashes follow the geometry of the outline, creating a kind of internal symmetry that feels almost architectural. The cut demands a very clean stone as inclusions have nowhere to hide, but in an eye-clean diamond, it produces an almost hypnotic depth. Its angular modernity also makes it surprisingly contemporary in diamond engagement ring designs.

Marquise Step Cut

The Marquise Shape with its elongated almond-like outline is almost always cut as a brilliant. The Marquise Step Cut is its rarer counterpart, and it exists in a fascinating tension between the geometry and brilliance of step-cut faceting.

Marquise Brilliant cuts focus on sparkle, movement and fire. Step-cut marquises are far more intriguing, sparkling brilliantly with the parallel facets that draw the eye inwards deep within the stone. The geometry of its edges become even more dramatic. It's a cut that rewards close inspection, almost demanding you look close into the stone rather than at its surface. 

Modified Octagon Cut

The Modified Octagon Step cut represents an emerald cut with the corners more deliberately expressed, becoming something else entirely in its modified form. "Modified" here can mean additional facets on the crown and slightly altered proportions. A hybrid approach that blends step-cut rows with brilliance on the pavilion. 

No two modified octagons are quite alike, and this is precisely what makes them interesting, and what makes them difficult to source. They are often the product of individual cutters working to specific commissions or simply following their own aesthetic instincts. Each stone is in some sense a one-off. For clients who value individuality, the modified octagon offers something the mainstream market largely cannot.

Oval Polygon Cut

Where the standard Oval Brilliant Cut silhouette is smooth and continuous, the Oval Polygon cut introduces faceted, flat-sided geometry to the outline itself, so the girdle traces a series of straight edges rather than a flowing curve. The overall impression is still oval, yet the eye reads the general shape immediately and up close, the stone reveals a more complex faceting.

This cut sits at a genuinely interesting intersection of organic and geometric sensibilities. The faceted outline changes how light enters the stone at the edges, creating subtle optical effects that a conventional oval doesn't produce. It also interacts differently with light and opens up the most unique design possibilities. It a deeply rare diamond cut and its visual rewards are considerable.

Oval Old Cut

The Oval Old cut is the predecessor to the modern Oval Brilliant. It is characterised by a small table, high crown, deep pavilion, and a large, open culet visible as a circle at the stone's centre when viewed from above. The Oval old cut applies that same sensibility to an elongated outline, and the result carries all the warmth and romance that old cuts are known for.

Old Cuts were designed for candlelight, and they still perform beautifully in these environments. They produce broad, soft flashes of colour what is known as diamond "fire". An Oval Old cut faceting is truly distinctive combined with a light performance that feels genuinely antique. Inspired by the 19th and early 20th century history of diamond cutting with brand new brilliance.  

Antique Pear Cut

The modern Pear Brilliant cut is engineered for maximum light return and strict proportional guidelines. The Antique Pear cuts tend to have a higher crown, wider proportions and a more pronounced curve on the rounded end. Historically, the proportions would vary considerably from stone to stone because they were cut by hand to whatever the rough would allow. The shoulders, the curves where the straight sides meet the rounded base, are often softer and less precisely defined than modern standards would permit. All of this adds up to a character revealing their beauty. 

In the current market, where vintage and antique stones are increasingly sought after for their distinctiveness, the Antique Pear cut is having a quiet moment as modern producers are cutting  But it remains far less discussed than old Europeans or rose cuts, which means that those who find them often do so below the premium that their beauty arguably warrants.

These cuts represent a living archive of creativity and rarity, to create the most beautiful and rare diamond cuts. Each one tells a story about a certain inspiration, what a particular cutter could achieve, and what the stone itself was willing to become. 

To begin creating your custom engagement ring in Melbourne with one of the rarest and most unique diamond cuts, fill in your details below