Round Diamond

When you think of an engagement ring it’s more than likely that you will envisage a Round Cut diamond as the center stone. And this is perhaps the reason that Round Cut diamonds have consistently been the most popular cut of diamond for engagement rings and other pieces of diamond jewelry. In fact, Round Cut diamonds account for over 75% of all loose diamond purchases and 60% of all engagement rings sold. This is possibly because Round Cut diamonds are the most versatile and wearable of all diamond shapes suiting most finger/hand shapes and appealing to a wide variety of tastes and budgets.

In short: The round brilliant is the most popular diamond shape worldwide and dominates the US engagement-ring market at 60-70% of 2025 sales. Standard cut has 57 or 58 facets (depending on culet), designed by Marcel Tolkowsky in 1919 for maximum light return. GIA's Excellent cut grade requires table 53-58%, depth 59-62.5%, crown angle 34-35°. Mohs 10 throughout. Lab-grown rounds run 60-80% below natural at identical 4Cs.

Round Cut diamonds offer a simple, classical beauty that is timeless and never out of fashion. They are uniform and symmetrical with 58 facets which qualifies them as a brilliant cut hence, why they are also referred to as Round Cut Brilliant diamonds. Their fire and brilliance is quite remarkable due to this faceting and so creates a stunning centerpiece and is one of the major reasons why choosing a Round Cut diamond is always the perfect option when looking for a timeless piece of diamond jewelry. Let’s take a closer look at the beauty of Round Cut diamonds.

THE HISTORY OF ROUND BRILLIANT DIAMONDS

The first circular shaped diamonds emerged with the invention in the late 1800s of the Bruting machine which enabled diamonds to be cut in a circular shape as opposed to the Cushion Cut which was previously the only option within this shape. The very first Round Cut diamonds were termed the European Cut, these diamonds are circular in appearance but very different from the current Round Brilliant Cut diamonds.

The Round Cut diamond seen in jewelry today was developed in 1919 Marcel Tolkowsky a Belgian gemologist and mathematician developed a formula for angling and cutting diamond facets to maximize light reflection and brilliance. Originally Tolkowsky specified that Round Cut diamonds should have 59.3% depth, 53% table and 34.50% crown angle. These specifications have been altered and perfected over time to further the level of maximize brilliance and sparkle that we see in todays’s Round Brilliant Cut.

CHARACTERISTICS OF ROUND BRILLIANT DIAMONDS

The Round Cut Brilliant diamond as we know it today has 58 facets (including the culet) and resembles a cone shape. These 58 facets are comprised of: 8 bezel facets, 1 table facet, 16 upper girdle facets and 8 star facets on the pavilion of the diamond. On the bottom part of a Round Cut diamond there are 16 lower girdle facets, 1 culet and 8 pavilion main facets. The ideal length to width ratio is 1.00 to 1.01.

All of these characteristics add up to create a diamond that has absolutely stunning brilliance and fire which is viewed by many as being far superior to that displayed by other diamond shapes. This is due to the fact that the cut style of Round Brilliant diamonds optimizes light reflections to a level not seen in other diamonds.

PROS AND CONS OF ROUND BRILLIANT DIAMONDS

PROS

The beauty of Round Cut Brilliant diamonds is indisputable. Due to the facet arrangement within this cut the amount of white light that reflects off the diamond’s table to the viewer, termed the ‘brilliance’, is maximized so creating a show stopping centerpiece. In fact Round Cut diamonds provide more brilliance than any other diamond shape.
The amount of colored light dispersed within a diamond is called the ‘fire’. Well cut Round Cut diamonds generate an exceptional amount of fire to give an almost rainbow effect across the diamond which is truly breathtaking.
The shape of round cut diamonds makes them the most durable of all the diamond cuts.
Round Cut diamonds have an enduring popularity and a timeless, graceful elegance that makes them a true investment piece that can be handed down through generations to come.
Round Cut diamonds are a very versatile shape which means that they are able to compliment a wide variety of jewelry styles. From vintage to contemporary, Round Cut diamonds make a stunning center stone or can be used equally as beautifully as accent stones.

CONS

On a per carat valuation basis Round Cut diamonds cost more than other fancy shapes due to low yield from the rough diamond and high demand versus low yield/supply. For example, a Round Cut diamond may cost 26% – 36% more than a similar fancy shape of the same carat, color and clarity.

DO ROUND BRILLIANT DIAMONDS REPRESENT GOOD VALUE FOR MONEY

Round cut diamonds are the most expensive of the diamond shapes commanding a premium price, This is because firstly, as they are so popular they can naturally command a higher price – this is simply market forces of demand and supply, Secondly, Round Cut diamonds yield a high percentage of waste from the cutting and polishing process. It is estimated that only 40% of the mined diamond is used to produce a single Round Cut diamond after cutting and polishing, meaning that 60% of the rough diamond is pure waste as it cannot be used to cut other diamonds. This therefore pushes up the pure carat price of Round Cut diamonds as diamond cutters are only producing one finished gemstone per rough diamond.

Having said that even though Round Cut diamonds are more expensive, when you purchase a Round Cut diamond you can rest assured that it is a true investment as this shape will never go out of fashion. Plus you have purchased a truly stunning diamond with the wow factor due to its superior brilliance, fire and sparkle.

← Back to Diamond Education