Radiant-Cut Diamonds Buying Guide: Modern & Durable

rose gold pave engagement ring - radiant-cut diamonds
This 2-ct radiant diamond is set in a rose gold ring with a delicate pavé band. The unique diamond shape adds a subtle twist to the classic solitaire engagement ring. You can get something similar at CustomMade. © by Bonnie Jewelry. Used with permission.


Radiant-cut diamonds are known for their brilliance and versatility. Invented in 1977, this modern diamond shape offers a unique look that stands out from the crowd. Whether you prefer an elongated or square-shaped diamond, a radiant cut will add a touch of elegance to your engagement ring. In this buying guide, we will explore the pros and cons of radiant-cut diamonds compared to other popular diamond shapes. We will also discuss how to evaluate the cut quality, clarity grade, and color grade for radiant-cut diamonds. Lastly, we will touch on lab-grown diamonds and provide tips on purchasing radiant-cut diamonds online.

Radiant-Cut Diamonds: Pros and Cons

Radiant-cut diamonds are renowned for their exceptional sparkle. Despite being a modern diamond shape, they can also exude a classic appeal. Their uniqueness and versatility make them an excellent choice for engagement rings. Let’s compare radiant cuts with other popular diamond shapes to help you make an informed decision.

Round vs Radiant

Radiants have a slightly smaller face-up size compared to round diamonds, approximately 4% smaller. However, the diagonal measurement of a radiant cut can create an optical illusion, making the diamond appear larger than a round brilliant of the same carat weight. Round brilliants provide the most light return and sparkle, but radiant cuts are also highly brilliant, resulting in a dazzling diamond.

Comparison between a simple solitaire ring with a radiant diamond and a classic round diamond
For a simple solitaire, a radiant diamond will make for an eye-catching choice, but you can never go wrong with the classic round. Images © James Allen. Used with permission.

Princess vs Radiant

The main noticeable difference between princess-cut diamonds and radiant-cut diamonds is their shape. Princess cuts have a square shape, while radiant cuts have beveled corners, making them more durable. The sharp corners of princess cuts are prone to snags and chips. Although radiant-cut diamonds are typically elongated, there are also square radiant-cut diamonds and elongated princess-cut diamonds.

Comparison between a princess-cut diamond and a radiant-cut diamond
The difference between a princess-cut diamond and a radiant-cut diamond is subtle, but both make great choices for an engagement ring. Images © James Allen. Used with permission.

Cushion vs Radiant

Cushion-cut diamonds have a gentle curvature, while radiant-cut diamonds have straight sides. If you are considering a three-stone ring setting, the outlines of radiants make them a great option. Cushion cuts display more dispersion or fire, which refers to flashes of colored light, compared to radiants. If you prefer this type of sparkle, a cushion cut may be the ideal choice for you.

Comparison between a cushion-cut diamond and a radiant-cut diamond
Notice the colored fire coming from the cushion-cut diamond on the left. Cushions are known for this effect, while radiant-cut diamonds give off more white sparkle. Images © James Allen. Used with permission.

Evaluating Cut Quality in Radiant-Cut Diamonds

The cut quality of a radiant-cut diamond plays a crucial role in its overall beauty. While there is no standardized grading system for radiant cut quality, there are certain factors to consider when evaluating a radiant-cut diamond. Let’s explore these parameters.

Shape Appeal

The appeal of radiant-cut diamonds largely comes from their shape. Ensure that the corners are evenly truncated and avoid diamonds with overly truncated corners, as they may appear off-shape. Take a close look at the shape of the diamonds to find the one that best suits your preferences.

Length-to-Width Ratio

Radiant-cut diamonds come in various length-to-width ratios (L/W). The choice of ratio is a matter of personal preference. Most consumers prefer an L/W of 1.15 to 1.35 for elongated shapes and under 1.05 for square radiants. Take a look at different diamonds to see which ratio appeals to you the most.

Bowtie Effect

Similar to other fancy shapes like ovals and pears, radiant-cut diamonds may exhibit a bowtie region—a dark band across the center of the stone. Poorly cut diamonds will have a prominent and unattractive bowtie effect. Ensure that the diamond sparkles well throughout, including the bowtie region, to guarantee its overall brilliance.

Depth and Table

Restricting the total depth percentage and table ranges can help narrow down your search for the best radiant-cut diamonds. A depth of 61-67% and a table of 61-69% are considered ideal for radiant cuts. However, there are exceptional diamonds outside these ranges, so you may explore more options within a broader range.

Best Clarity Grade for Radiant-Cut Diamonds

To maximize your diamond budget, consider choosing a radiant-cut diamond with the minimum clarity grade that does not compromise its appearance. The intense brilliance of radiant cuts makes it difficult to spot inclusions in lower clarity grade diamonds. Generally, SI1 and SI2 clarity grades offer eye-clean diamonds. If budget allows, consider VS2 clarity for diamonds two carats and above, as larger diamonds may show inclusions more readily.

An SI2 clarity diamond with inclusions impossible to find with the naked eye
The inclusions in this SI2 clarity diamond would be impossible to find with the naked eye. © James Allen. Used with permission.

Best Color Grade for Radiant-Cut Diamonds

Radiant-cut diamonds, like other fancy shapes, tend to show more color compared to round brilliants. However, an H or I color radiant will appear white in any engagement ring setting. Some J and K color diamonds can also look great, especially when set in yellow or rose gold. Even the top color grades (D-F) may show a slight tint due to the reflection of metal color. Consider your preferences and budget when selecting the color grade for your radiant-cut diamond.

Ring featuring a radiant-cut diamond
Find this Ring at James Allen

Radiant Cut Lab Created Diamonds

Should I Buy a Radiant Cut Lab Grown Diamond?

The decision to purchase a radiant cut lab-grown diamond depends on your personal preferences and priorities. Lab-grown diamonds are chemically identical to natural diamonds and often offer cost savings compared to mined diamonds. If you value ethical considerations, lab-grown diamonds are typically more environmentally friendly and free from concerns related to the diamond mining industry. Consider factors such as your budget, environmental impact, and desire for a responsibly sourced gemstone when making your decision.

How to Buy a Radiant Cut Lab Grown Diamond

When purchasing a radiant cut lab-grown diamond, there are key steps to follow. Determine your budget and desired specifications, such as carat weight, color, clarity, and cut. Research reputable jewelers or online retailers specializing in lab-grown diamonds, and read customer reviews to ensure credibility. Compare prices and options from different sources. Inspect the visual appearance of the diamond through magnified images or videos to assess its brilliance and sparkle. Finally, make your purchase from a trusted source that provides transparent information, warranties, and a return policy.

Finding the Best Radiant-Cut Diamonds Online

If you are considering buying a radiant-cut diamond, it is essential to see the diamond up close to assess its cut quality and clarity. James Allen and Blue Nile offer magnified, 360° videos of their diamonds, making them the top choices for purchasing radiant diamonds online. James Allen has an advantage for engagement ring selection, offering a wide range of settings. On the other hand, Blue Nile allows you to filter results by length-to-width ratio, making it a great option for finding a replacement stone. For a truly unique experience, consider working with CustomMade, where jewelry experts can help you find the best stone for your style.

In conclusion, radiant-cut diamonds are a captivating choice for engagement rings due to their modern yet timeless appeal. Consider the pros and cons compared to other diamond shapes to determine your preference. When purchasing a radiant-cut diamond, evaluate the cut quality, clarity grade, and color grade to ensure you find the perfect diamond for your budget and style. Lab-grown diamonds offer an ethical and cost-saving alternative. Lastly, choose a reputable online retailer and explore their comprehensive selection to find the best radiant-cut diamond that captures your heart.

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