Round Diamond: Buying Guide

No one can rival the timeless allure of the round-cut diamond. Among all the cuts in the history of diamonds, none have commanded such widespread admiration as this remarkable shape. Its enduring reign as the top choice is not without reason. The round diamond’s extraordinary radiance, derived from its flawless symmetry, is the secret behind its everlasting popularity.

The rise of the round diamond can be attributed to Marcel Tolkowsky’s groundbreaking thesis, “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond,” published in 1919. Tolkowsky’s work revolutionized the understanding of the round-cut diamond by establishing the optimal proportions to enhance its brilliance and fire. While Tolkowsky’s initial specifications included a 53% table, 59.3% depth, 34.50 crown angle, and visible culet, these guidelines have evolved with advancements in round diamond cutting techniques. Thanks to theoretical advancements and the use of cutting-edge technologies like laser cutting, diamond manufacturers in Belgium have embraced these innovations, resulting in the breathtakingly brilliant cuts seen in exquisitely crafted round diamonds today. 

This article intends to provide you with an education on the fundamentals of the round-cut diamond and the essential factors to consider before making a purchase.

What is a Round Cut Diamond?

Round diamonds have mesmerized enthusiasts with their exquisite beauty for centuries. However, achieving the exact proportions and symmetry required for these diamonds has only become a recent technological triumph. Before the development of this crucial technology, diamonds with somewhat round shapes in the nineteenth century were commonly known as Old European Cuts (OEC) or Old Mine Cuts (OMC). 

Now that you are familiar with this shape, let us focus on the important factors that you need to consider before buying a round diamond. 

3 important steps to buying round-cut diamonds

Cut Quality: Proportions for Round Cut Diamonds

When it comes to choosing a round diamond, the cut takes center stage as the most crucial factor among the 4Cs that deserves your utmost consideration. This is because the cut directly impacts the diamond’s sparkle and overall visual allure.

Esteemed gemological laboratories like GIA thoroughly assess the cut quality of round diamonds and assign grades ranging from Excellent, Very Good, Good, and Fair, to Poor. To achieve the best outcome, we strongly advise prioritizing diamonds with an Excellent cut grade (or Ideal if graded by AGS) when embarking on your diamond shopping journey.

Choose The Best Color Range

Round diamonds possess a distinct facet pattern and cutting style that sets them apart. It allows for a higher level of light reflection compared to other diamond shapes. This exceptional ability to reflect light enables round diamonds to mask color tints with their dazzling sparkle, eliminating the need for a high color grade to achieve a brilliant white appearance.

While D-F (colorless) diamonds offer you a captivating cool and icy look, they are highly sought after and come with a heavy price tag. For pragmatic diamond shoppers, choosing a G color rating is a wise choice as it allows you to avoid excessive costs while still obtaining a diamond with a white appearance.

However, it’s important to recognize that selecting a diamond’s color often boils down to personal preference. If you’re unsure about your preferences, we suggest watching the going for D, H, and K color diamonds, so that you can make an informed decision.

For further information, you can check out GIA’s color chart.

Clarity Grades for Round Brilliant Cut Diamonds

GIA evaluates diamond clarity on a scale ranging from FL (Flawless) to I3 (Included 3), with Flawless being the highest grade and Included 3 being the lowest. One common misconception, especially among beginners, is that a higher clarity grade automatically guarantees superior sparkle and brilliance.

However, this is far from reality. The truth is that the majority of VS2 diamonds that are free from visible inclusions appear just as dazzling as internally flawless diamonds to the naked eye. Unless you specifically desire a symbolically flawless D/IF rating for your diamond, you can save a significant amount of money by selecting an eye-clean SI1 or VS2 diamond.

In general, most SI1 and VS2 diamonds are eye-clean and offer excellent value for your investment. The key is to look for stones that are devoid of visible inclusions without the need for a 10X loupe to detect them. By doing so, you can make wise decisions and obtain the best value for your money.


When you’re shopping for round diamonds, it’s crucial to give priority to the quality of the Cut, while also keeping in mind our additional tips to help you stay within your budget. Round diamonds possess an enduring charm and remarkable versatility. They come in a diverse range of sizes and can be set in various settings according to your personal preference. However, if you need further guidance about the diamond shape, visit https://uniglodiamonds.com/. They hold a prominent position in the diamond market, assisting their customers in finding the perfect shape within their budget.

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