Understanding Diamond Shape
Which shape appeals to you most? Here are some facts to help you decide.
3/4 of all diamonds sold are round brilliant cuts making them the most popular by far. The ideal proportions of a round cut have been perfected over time to maximize light return (brilliance) and dispersion (fire). Advancements in technology have helped to produce the incredibly brilliant cuts we see today. A typical round diamond (for example; a 1.00 carat, F-color, VS2-clarity, Ex cut) may cost 25-35% more than a similar fancy shape. Round diamonds cost more on a per carat basis than fancy shapes for two reasons; the demand for round diamonds is very high, and the yield is relatively low because more of the rough stone is lost in the cutting of a round diamond than in cutting fancy shapes.
Round brilliant cuts are the most versatile of diamond shapes and can take many different types of setting styles. View our style gallery for some ideas.
The princess cut is a square or rectangular modified brilliant diamond cut with a distinctive “crushed ice” or needle like facet pattern. They are a very popular fancy diamond shape, especially for engagement rings because of their unique shape, sparkle, and relative price. This cut hides inclusions very well because of the light dispersion from the extra facets it contains. A higher yield is obtained when cutting a princess from the rough crystal than cutting a round and this means lower prices for the princess. They display a more consistent brilliance and scintillation than other longer fancy shapes. On the down side princess cuts have a smaller diameter than a round cut for the same carat weight so can appear smaller.
All other factors being equal, the more rectangular a princess cut diamond, the lower the price. A slightly rectangular princess with the longer length worn parallel to the finger is often preferred as this can be more complimentary.
Because the corners of the princess cut were at the outer edges of the original rough diamond crystal, this is where you can often expect naturals, inclusions and extra facets. The sharp, squared-off corners of the princess cut require great care when setting and need to be protected to avoid chipping or cracking. This is why when a round claw is used it tends to be much larger than that of a round claw on a round brilliant. We prefer to use “V” shaped claws on the corners of a princess cut as they offer better protection. The princess is also commonly used in channel setting in diamond wedding and eternity rings because the stones sit side by side without any gaps in between. They are harder to set than round brilliants so have a higher setting cost.
The radiant cut is a cut-cornered, rectangular or square modified brilliant. They have (in common with princess cuts and some cushion cuts) a distinctive “crushed ice” or needle like facet pattern and as a result have much greater brilliance and fire than the emerald or asscher cut. A square cut radiant will have better sparkle than the princess cut. With the increase in popularity of square cuts, radiants are now more commonly cut square or nearly square. In longer, rectangular radiant cut diamonds, a bow tie effect is more likely (although not as common as in oval, marquise, and pear cuts). Rectangular diamonds have less symmetry than square diamonds and need greater depth (which translates to higher carat weight) to achieve similar brilliance so squarer cuts are more cost effective. With no recognised standard for proportions, the quality of the cut varies considerably as the cutter will try to achieve maximum yield from the rough crystal. Personal evaluation and comparison of a selection of radiant cuts is the best way to judge for yourself their individual beauty.
The claws securing a radiant are less obtrusive than those required for the sharp corners of a princess and tend to give a more pleasing result so they are a great alternative to a princess solitaire. The cropped corners also help to minimize chipping. Radiant cuts can look very effective with various options of sides stones in trilogies and as a centre stone in halo rings.
Asscher cut is a squarish step cut with deeply cut corners which give it an octagonal outline. It differs from a emerald cut with a higher crown and a deeper bulging pavilion, smaller table and larger step facets. These features give it more brilliance and fire than an emerald cut. A well cut asscher will appear to have concentric squares as you look down through the table. The depth of the cut means the asscher has the smallest size per carat of all the fancy shapes. Each stone must be seen and evaluated individually; there is no standard pricing for this type of stone since most are unique. Like all diamond shapes, picking the “best” Asscher means finding the right balance of beauty, size and price. Colour and clarity are easier to see in an asscher cut diamond, especially in larger stones because of the large, open facets which allow you the see through the diamond so allow at least one grade higher in colour and clarity compared to brilliant cuts to offset this.
Due to the deep bulging pavillion the Asscher cut doesn’t lend itself to flush-fit (where the engagement ring will sit flush to the wedding ring). The setting needs to be taller and more vertical compared with other diamond shapes so if you want a narrow band with your setting a shaped to fit wedding ring is often necessary.
The unique look of the emerald cut diamond is due to the step cuts of its pavilion and its large, open table. Instead of the sparkle of a brilliant-cut, emerald cut diamonds produce a hall-of-mirrors effect, with an interplay of light and dark planes. The emerald cut reveals a classic beauty and elegance not seen in other cuts. The look of an emerald cut diamond is subtle and understated with less “flash,” or reflection and refraction. The shape was originally developed for the cutting of emeralds, thus the name. Emerald cut diamonds are rectangular but can vary from nearly square to very long and narrow. The classic emerald cut diamond has a length to width ratio of around 1.50. If you prefer the look of the square emerald cut diamond, you should consider the asscher cut as well. Colour and clarity are easier to see in an emerald cut diamond, especially in larger stones because of the large, open facets which allow you the see through the diamond. Allow at least one grade higher in colour and clarity compared to brilliant cuts to offset this.
The Cushion cut is a modern version of the old mine cut which was the standard diamond cutting style for diamonds before the turn of the century. A cushion cut is a square or squarish-rectangular cut with rounded corners and brilliant-style facets. Cushion cuts are a little less brilliant than modern round brilliants but have more fire. Traditional cushion cut diamonds have steep crown and pavilion facets, usually a large culet and a small table and return light in a chunkier pattern than modern cuts. The cushion cut style has been refined over time, shrinking the culet, enlarging the table, and improving the cut angles for increased brilliance. Modern cushion cuts also have better symmetry, proportions and polish and can be the most similar to brilliant cuts in appearance with a more unusual shape. The standards for cushion cuts vary more than most other shapes. The newest method of cutting cushion cuts adds an extra row of facets to the pavilion or bottom of the diamond. Classified by GIA as a “modified” cushion cut they have a “crushed ice” or needle like facet pattern, more similar to a radiant cut than a traditional cushion cut. Cushion cut diamonds come in various shapes from those almost square to very rectangular. There is no right answer so personal preference should dictate choice. Rectangular cuts have less symmetry than squarer cuts and need greater depth (which translates to higher carat weight) to achieve similar brilliance so squarer cuts are more cost effective. With rectangular cuts, if the cut of the diamond is not correct a bow tie shadow will be evident across the centre of the diamond (similar to an oval cut). You need to examine the diamond in person under varying light conditions to ensure you do not have a persistent dark bow tie pattern.
Rim settings will accentuate their unusual shape while claw settings will make them appear more square/ rectangular. Cushion cuts with more rounded corners are often set with double claws as they hold the diamond more securely. Cushion cuts are nearly as versatile as round cuts and can look very effective with various options of sides stones in trilogies and as a centre stone in halo rings.
The oval modified brilliant cut it like a stretched round brilliant cut, with similar fire and brilliance to a round cut except across the centre were the “stretched” facets can leak light giving a darker area known as a bow tie. This can vary from near invisible to severe. The severity of a bow-tie can only be judged by personally viewing the diamond. Like all fancy shapes there is no ideal cut in terms of proportions but the classic oval cut has a length to width ratio of 1.35 – 1.50. A thinner oval can work well in a trilogy ring and a wider shape may suit a solitaire better but the proportions of the fingers will also influence suitability. Apart for the minimum of bow-tie, personal preference should be the main deciding factor. The oval is a good option if you want something like the round brilliant but a little more unusual. Having a larger surface area than the round cut of the same carat weight and also being at a lower price point they give good impact at a lower budget. Allow at least one grade higher in colour than round brilliants as ovals appear yellower due to there shallower cutting style. The oval cut diamond’s elongated shape can make the finger of the wearer appear longer and slimmer.
The pear cut is modified brilliant cut combining a round and a marquise shape, with a tapered point at one end. Like marquise cuts a pear shaped diamond should possess excellent or very good symmetry, with uniform, symmetrical curves and the point lining up with the apex of the rounded end. The classic pear shaped diamond has a length to width ratio of 1.40-1.70 but like other fancy shapes, the cutter will have tried to obtain maximum yield from the rough crystal so a variety of slim to wide cuts exist. Pear shaped diamonds possess some degree of bow tie, varying from near invisible to severe. The only way to determine the extent of bow tie is to view the diamond in person. In rings, finger length and appearance, orientation of setting and ring style, whether solitaire or multi-stone can all influence personal preference for wider of more slender pear cuts. Pear cuts also make attractive side diamonds in trilogy rings. Pear cut shapes make very attractive pendants and drop earrings. Always look for at least one grade higher in colour than round brilliants as pear cuts appear yellower due to there shallower cutting style.
Since the pointed end of the pear cut was close to the outer edges of the original rough diamond crystal, this is where you can sometimes expect naturals, inclusions and extra facets. Great care is required when setting and the point needs to be protected to avoid chipping or cracking. a “V” shaped claw is used to give protection. A pointed tip with insufficient girdle thickness presents durability problems, while an extremely thicker girdle can cause difficulty in setting and hides the weight below the girdle where you can not see it.
The marquise cut is a pointed oval, modified brilliant cut. Like pear cuts a marquise shaped diamond should possess excellent or very good symmetry, the two pointed ends correctly aligned and with uniform, symmetrical curves. A length to width ratio of 1.75 -2.15 is considered the classic marquise shape but like other fancy shapes, as the diamond cutter will try to obtain maximum yield from the rough crystal a variety of slim to wide cuts exist. Personal preference should dictate choice. Marquise cuts possess some degree of bow tie, varying from near invisible to severe. The only way to determine the extent of bow tie is to view the diamond in person. Carat for carat, the marquise diamond has one of the largest surface areas of any diamond shape and as the marquise diamond is long and narrow, it can also create the illusion of greater size, making it great value for money. Like the oval diamond, the marquise cut diamond’s elongated shape can make the finger of the wearer appear longer and slimmer. Always look for at least one grade higher in colour than round brilliants as marquise cuts appear yellower due to there shallower cutting style.
As the pointed ends of a marquise cut were nearest the the outer edge of the original rough diamond crystal, this is where you can sometimes expect naturals, inclusions and extra facets. Great care is required when setting and the points needs to be protected by “V” shaped claws to reduce the possibility of chipping or cracking. A pointed tip with a very thin girdle presents durability problems, while an extremely thick girdle can cause difficulty in setting and hides the weight below the girdle where you can not see it.
For the incurable romantic the modified brilliant-cut heart shaped diamond is the perfect symbol of love. When choosing a heart, symmetry is a very important characteristic, since it is critical that the two halves of the heart are identical. The cleft (between the two lobes) should be sharp and distinct, and the wings (the sides as they curve down to the point) should have a very slightly rounded shape.
Heart shaped diamonds of less than 0.50ct may not be a good choice, as the heart shape is more difficult to perceive in smaller diamonds, especially after they are set in claws. If claw set, one claw on each lobe and one claw at the point will better display the heart shape outline. A rim setting will show off their unique shape better.
Understanding The 4 C’s
Each individual stone’s beauty and cost will be influenced by its cut, colour, clarity and carat weight. It’s all about judging what is most pleasing to you. View this 4 C’s guide to understand this grading better.