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Round-Cut Diamonds

Many times, when you picture an engagement ring in your mind, you automatically see a brilliant solitaire: a single, perfectly cut round-shaped diamond in a prong setting. Or when someone mentions they received a diamond pendant, you often picture a round cut diamond in a simple solitaire setting.

While the ring and the pendant may be different in actual looks, the mind sees the single, sparkling round-cut diamond. The round-cut diamond has been the ideal and preferred diamond cut since diamonds were first worn. And, as the most popular cut, the breathtaking shine of the round-cut diamond lends itself to a variety of jewelry styles.


Illustration of a round-cut diamond

What is a Round-Cut Diamond?

Round-cut diamonds are the most popular diamond shape, making up almost three-quarters of all diamond sales worldwide. Round-cut diamonds are known for their fire, brilliance and scintillation, which, if cut well, is unattainable by other diamond shapes.

The round-cut diamonds we see today have generations of research behind them with the intent of creating the best shape fir ultimate brllliance. At least six ideal cuts have been created throughout diamond history, all working toward today’s modern brilliant round-cut diamonds. These ideal cuts include:

  • Practical Fine Cut
  • Parker Brilliant
  • Ideal brilliant
  • Eulitz Brilliant
  • American Standard

Each of these cut styles feature unique benchmarks for crown height, pavilion depth, table diameter, girdle thickness, crown angle and pavilion angle — all adding up to a unique level of brilliance.


What Do You Call a Round-Cut Diamond?

The shape (also called the cut) of a round-cut diamond is made up of 57 or 58 facets (sides), which may include a culet - the tiny point at the base of the diamond. In a uniformly cut diamond, the facets should meet at a perfect point – and these diamonds will have no culet. When a culet is present, the diamond is referred to as having 58 facets.

The diamond industry recognizes two distinct types of round-cut diamonds:

Brilliant-Cut Round Diamonds

The brilliant cut diamond utilizes its facets to reflect light particularly well. With this diamond cut, angles and proportions work together to reflect light, called scintillation. Brilliant cut diamonds are classified as having a medium to large culet, and a lower half that is 65 percent or less of the total length of the diamond. In modern jewelry, Brilliant-cut round diamonds are an excellent choice.

Old European-Cut Round Diamonds

The old European-cut round diamond was created before modern diamond technology and was popular prior to the 20th century. These diamonds generally have deeper proportions than the round brilliant-cut diamond. Old European-cut diamonds were primarily cut for their colour. If your partner prefers a more vintage look, an Old European-Cut diamond might just be the perfect choice.

When comparing brilliant-cut and old European-cut diamonds, the main difference is in the facets. Old European-cut diamonds feature facets with triangular blocks, where the round brilliant-cut diamonds have thinner kite-shaped facets. Each cut style reflects light in uniquely beautiful ways.

During the process of cutting a round diamond, much of the rough diamond is lost. Because of this, round-cut diamonds tend to be more expensive than other diamond shapes of similar size. However, because of the way they are cut, round diamonds give the appearance of being the largest of all shapes with the same carat size. People continue to favor the shape of the round-cut diamond because of its brilliance and beauty. The round cut is the preferred shape and is commonly found in fine jewelry, including engagement rings.


History of the Round-Cut Diamond

Round diamonds are the most popular diamond choice in jewellery today — accounting for as much as 75 percent of all diamond sales. And with modern diamond cutting technologies, round-cut diamonds are even more brilliant than ever before.

The popularity of round diamonds is nothing new. The round diamond shape gained traction in 1919, the year that Marcel Tolkowsky published his thesis titled “Diamond Design: A Study of the Reflection and Refraction of Light in a Diamond.” In his thesis, Tolkowsky discussed the ideal cut of diamond for optimal brilliance and shine, citing specific angles and proportions as being particularly useful to maximize brilliance. Tolkowsky’s work created a surge of recognition for the round-cut diamond, and the shape has remained as the most popular diamond shape ever since.

If your goal is to find a timeless and classically beautiful diamond, then a round-cut diamond may be the right option. Round diamonds are fashioned to meet modern concepts of beauty – often described as being classic and elegant. Gemological laboratories grade round-cut diamonds on a number of classifications, ensuring that each diamond meets the high-quality standards the industry demands.


Grading System of Peoples’ Round-Cut Diamonds

At Peoples, we rely on trusted experts from different gemological laboratories to grade our precious stones.

To determine a diamond’s grade, these labs inspect each diamond under closely controlled lighting and viewing conditions. Trained grading professionals use highly calibrated measurement devices to capture important data for use in determining the round diamond’s quality. These experts will then grade our round-cut diamonds on the following determinations:

Round-Cut Carat Weight
The weight of the diamond is measured using the carat system. Our experts use specialized scales to ensure an accurate weight measurement. The weights are measured to the hundred-thousandths of a carat. With the carat system, one metric carat is equal to 0.2 gram.

Round-Cut Clarity
Round diamond clarity refers to the appearance of the stone, and it notes any blemishes or inclusions. Our experts grade round diamond clarity as one of six grades – Flawless, Internally Flawless, Very Very Small Inclusions, Very Small Inclusions, Small Inclusions, or Imperfect.

Most important when looking at the clarity of a diamond is whether or not the diamond appears to be clear to the human eye. Many blemishes may only be visible to a professional with highly specialized equipment. When looking at diamonds, a lot of the decision process is subjective. Some people may prefer knowing that their diamond is certified as flawless while others may be okay with minor blemishes that are invisible to the naked eye. If your partner prefers a more flawless appearance for their diamond jewellery, you’ll want to choose a Flawless or Internally flawless diamond. If small imperfections do not stand out to your partner, then a Very Small Inclusions or Small Inclusions grade may be preferred.

Round-Cut Colour
The industry standard for grading round diamond colour is a system that begins with a D grade (colourless) and continues with increasing levels of colour to a Z Grade. Diamonds are compared to master stones with known colour grades. Our experts utilize master stone sets that are rigorously chosen and tested prior to use.

To the naked eye, the colour of the diamond is closely tied to the size of the round diamond and the setting. The differences in diamond colour are difficult to see for the human eye, but they may still affect the price of the diamond. Additionally, the setting colour and material chosen for the round-cut diamond can make an immense difference in the colour of the diamond. Ideally, a diamond should always look colourless against its setting, so keep in mind what the setting will look like when shopping for diamond colour. For instance, yellow-tinged diamonds will look best set in yellow gold, while less coloured diamonds will shine in.

Round-Cut Quality
The proportions of a round-cut diamond determine how brilliantly the diamond will shine. Grading of a diamond’s cut is determined by examining its angles, facets, and polish. The goal with attaining a good cut of diamond is to create a diamond that has the correct proportions to allow the maximum amount of light to travel through, which will give the diamond a beautiful sparkle that your partner will love. Each diamond is given one of the following grades for cut: Ideal, Excellent, Very Good, Good, Medium, Fair, or Poor. A high-quality diamond cut will feature proportions that allow optimal light reflection through the crown and table – giving off a beautiful, brilliant sparkle.


Round-Cut Diamonds: Conclusion

For centuries, round diamonds have been the most popular diamond shape in the consumer market – especially popular for engagement rings, necklaces, and other fine jewelry. This brilliant shape of diamond is fashioned to meet modern concepts of beauty, with a timeless and classic style. Round-cut diamonds feature incredible brilliance and fire that sparkles in the light, made possible by strict guidelines for ideal proportions. These guidelines evaluate the round diamond’s facet shape, angles, girdle width, culet size, polish, and symmetry to determine the grade of the diamond.

For a classic and beautiful diamond option, the ideal proportions of round-cut diamonds offer timelessness and elegance, as well as brilliant shine. As the most researched diamond shape in the industry, the round-cut is backed by advanced scientific theories of light reflection, mathematical calculations, and centuries of modernization.

Browse our selection of unique Peoples round-cut diamond engagement rings to find the style that shines as bright as the one you love.