Round diamonds are, by far, the most popular style of diamond for use in diamond rings. That's not just a British thing; globally, around 75% of all diamonds sold are round. More than that, almost all round diamonds are brilliant cut. There's a good reason for this massive degree of popularity: round diamonds show off the gem in the best possible way. If you want your diamond to sparkle to the best possible degree, then the mathematics and physics dictate that the diamond must be round, and it must be brilliant cut.
No other shape of a diamond has the flash and brilliance of a well-cut round gem.
The Perfect Engagement Ring
Any of the brilliant round cut shapes are perfect for an engagement ring, all designed to give the best brilliance. The proportions of round cut diamonds are aesthetically pleasing; the shape is what women expect to see in their engagement ring.
The round shape has, therefore, become the standard for engagement rings and all other types of ring.
The Perfect Shape For A Diamond
Owners of diamond jewellery have always wanted to have the most brilliant gems possible. The earliest effective attempts to create brilliant diamond cuts began in the 17th century with the Mazarin cut, named after its creator, Cardinal Mazarin. The Mazarin cut was developed during the 18th century leading to the Peruzzi cut and then the old European Cut.
The modern round cut diamond was devised in 1919 by Marcel Tolkowsky, an engineer born into a Polish diamond cutting family. Marcel understood that to create the maximum sparkle or brilliance, every surface of the gem had to be cut perfectly to keep light reflecting within the gem. The Tolkowsky design sought to allow light to escape only from the top of the stone.
Most round diamonds have 58 facets (the flat polished surfaces 0f the cut diamond). In some designs where there is no small facet (the culet) at the bottom of the diamond, there will be 57 facets.
Although Tolkowsky’s design was a revelation in terms of getting the most brilliant diamond, it is not perfect. Modern computers and improved cutting techniques have led to even better designs. Bruce Harding, in the 1970s, developed a new method for modelling the way light rays travel through the diamond. Bruce's work has led to computer models and new developments making diamonds even more brilliant, with even more sparkle.
The Three Main Round Cut Patterns
1. Modern Brilliant Cut (Tolkowsky)
The Modern Brilliant Cut, as devised by Tolkowsky, is the most popular cut for diamonds. This cut as relatively long lower half facets that some think can make the diamond look somewhat 'splintery' a comment on the balance of proportions between the top and bottom of the diamond. Of course, the lower part of the diamond is usually hidden in the setting of the stone.
2. Round Brilliant (Old European Cut)
The Old European Cut is an earlier attempt to maximise the brilliance and sparkle of diamonds. The facets of this cut are larger than the Tolkowsky design.
To identify an Old European Cut diamond look through the top of the diamond. If the culet (bottom facet) is visible, then the gem is likely to be Old European Cut. On diamonds larger than 1 carat the culet is probably evident to the naked eye.
Other distinguishing features are a large table (top facet), a frosted girdle (the girdle runs around the middle of the diamond. In some designs this is polished or, itself faceted.
Although this cut is less brilliant than the Modern Cut, some buyers prefer the proportions of diamonds cut in this style.
3. Circular Cut
The circular cut was introduced in the late 19th century when the first cutting machines capable of cutting fully circular gem were introduced. Circular cut stones look similar to Modern Cut stones with similar proportions. The lower facets are shorter than in Modern cut, giving a shape that some buyers prefer.
Hearts And Arrows Show The Best Quality Of Diamond Cutting
The best quality diamond cutting can create an effect in a round cut diamond called 'hearts and arrows.’ When the diamond is looked at from above, the diamond will show a pattern that looks like a series of 8 arrows. When viewed at from below, there is a pattern of 8 hearts. For this effect to be visible, the entire diamond must be cut with excellent symmetry. The top facet must be perfectly perpendicular to the bottom of the diamond (the pavilion).
The Costliest Cut Of All
Even though round diamonds are, by far, the most popular shape, they are also the most expensive to buy compared to every other cut. There are good reasons for this.
When a diamond cutter creates a cut diamond, he is concerned to do so with the least possible waste of expensive diamond material. The round cut due to its shape and number of facets is not an economic shape to cut; there is a lot of wastage. Even with modern cutting techniques, there is a loss of more than 50% of the diamond’s original weight. This wastage makes the cut cost of a round cut diamond higher than for other cuts. At the same time, because the demand for round cut diamonds is high, market forces tend to push the prices of these diamonds higher than for less popular styles.
As a rough guide, you can expect to pay for a round cut diamond around 25-35% more for a round cut diamond of identical weight, clarity and colour than for other shapes.
If you are in the market for diamonds as an investment, then a round cut is the best choice, but it needs to be quite large. Investment grade diamonds come in at sizes upward of 5 carats, and almost always it must be a round cut.