Five Fun Facts About Round Cut Diamonds

posted in: CaratsDirect2U Updates | 0

Round Cut Diamonds – A Brief History

Despite being the most popular diamond cut today, the 58-facet brilliant round cut diamond as we know it today has only existed for the past 100 years. In the late 1800s the diamond cutting machine, also known as a diamond bruiting machine, was invented. This machine allowed for a far more accurate cutting process and paved the way for the first fully rounded diamonds to be produced.

However, the European cut diamonds, the first truly round diamonds, were very different to the round cut diamonds we are used to seeing today. The round diamonds we find in today’s diamond solitaire engagement rings are as a result of Marcel Tolkowsky’s studies on diamonds and the refraction of light. Here are five interesting facts about round cut diamonds that you may not have known.

1. Most Popular and Most Expensive Diamond Cut

An astonishing 70-80% of diamonds manufactured today are round cut diamonds. Round cut diamonds have been the most popular diamond shape for almost a century, being the most used diamond for solitaire diamond engagement rings. They are also the most expensive diamond cut, but not solely because the demand is higher than for other loose diamond cuts.

The yield for a round cut diamond is quite low, meaning that more of the diamond is lost in the cutting process than fancy shapes such as princess or radiant cut diamonds. This contributes to round cut diamonds costing 25% – 35% more than other diamond shapes. For example, a 1.03 carat round cut diamond with a VS clarity and G color grade would cost more than a marquise diamond with similar characteristics.

2. 58 Facets Mean Ample Brilliance and Light

In 1919, Tolkowsky published his thesis titled: “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond”. In this publication he described how he used mathematics to calculate the ideal proportions for maximizing the brilliance and fire of a round cut diamond. The diamond industry embraced this study and have used it to reach even better results over time.

3. Advances in Technology Perfect the Round Cut Diamond

Over the past 100 years, diamond cutters have improved the technology they use in their diamond cutting to perfect the cutting process and maximize the brilliance and fire produced by round cut diamonds. More recently, lasers are commonly used in diamond cutting. As a guide, according to GIA standards, a round cut diamond with a 53-58% table width, 59-62.3% depth and 34-34.9 crown angle will be given an “Excellent” cut grade.

4. Round Cut Diamonds on the Red Carpet

As the most popular diamond cut, many celebrities have been given impressive round cut diamond engagements rings. For example, when Evan Spiegel proposed to model Miranda Kerr in the summer of 2016, he presented her with a beautiful round cut diamond ring with a taper diamond on each side.

Similarly, film director Sam Esmail presented a large round diamond engagement ring flanked by two white baguette diamonds on a platinum setting when he proposed to actress Emmy Rossum.

5. 4 Prong Setting Ideal for Solitaire Diamond Engagement Rings

The most commonly used setting for the round cut diamond engagement ring is the 4 prong setting. Not only is the 4 prong setting very secure, it is also a very open setting, allowing the optimum amount of light to enter the stone. For round cut diamonds over 2 carats, a 6 prong setting may be required to keep the stone secure.

The bezel setting, while unique and modern, is less used for the round cut diamond as it will prevent a large amount of light coming through, which is one of the key selling points of round cut diamonds.

If you have any questions about purchasing round cut loose diamonds online, we can always be contacted on 1-800-557-7095 where one of our expert diamond jewelers will be happy to assist you. Alternatively, you can email us at with any questions you may have.