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The buyers' guide to radiant cut diamonds

Loose radiant cut diamond

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Radiant cut diamonds combine the elegance of the emerald cut's outline with the sparkle of brilliance faceting. Boasting 70 facets, they are revered for their dazzling light performance, making them an increasingly popular choice in recent years.

In this guide, we'll walk you through the defining characteristics of radiant cut diamonds, the history and development of the cut, the pros and cons, and what to consider when choosing a radiant cut diamond.

What is a radiant cut diamond?

The "radiant cut" is a specific style of diamond cut defined primarily by its shape and faceting pattern and is characterised by exceptional brilliance and fire.

Radiant cut shape

Radiant cut diamonds can have square or rectangular proportions, but they stand out because of their cropped corners. As a result, their outline is similar to emerald cut and Asscher cut diamonds, but they are differentiated from these cuts by their distinctive facetting pattern.

Radiant cut diamonds with various different length-to-wodth ratios
Radiant cut diamond with length-to-width ratios of 1, 1.3 and 1.8 (left to right)

Square radiant cuts are defined as those with a length-to-width ratio between 1 and 1.05, while rectangular radiant cuts are those with a length-to-width over 1.05, though typically rectangular radiant cuts have a length-to-width ratio of 1.3 or more. 

Radiant cut faceting pattern

The radiant cut has a unique facet pattern that combines the best features of both round brilliant and emerald cuts. This fusion results in a lively and vibrant diamond that displays a mixture of brilliance (the white light reflections) and dispersion (the colourful flashes or "fire").

Its 70 facets are distributed across the crown, pavilion, and girdle as follows:

radiant cut faceting patterns
Rectangular vs. square radiant cut faceting patterns
  1. Crown (Upper Portion of the Diamond):
    • Table Facet: This is the large, flat top facet of the diamond. It plays a crucial role in the diamond's light performance.
    • Star Facets: Surrounding the table, there are usually 8 star facets.
    • Kite Facets: These are 8 in number and are found just outside the star facets.
    • Bezel Facets: Typically, there are 8 large bezel facets on the crown.
    • Upper Girdle Facets: Located at the outer edge of the crown, there are 16 upper girdle facets.
  2. Pavilion (Lower Portion of the Diamond):
    • Lower Girdle Facets: Directly below the upper girdle facets, there are 16 lower girdle facets.
    • Pavilion Main Facets: There are 8 of these, and they meet at the culet (the small facet at the bottom tip, though not all radiant cuts will have a culet).
    • Additional Facets: Depending on the specific variation of the radiant cut, there may be additional facets on the pavilion to enhance the diamond's brilliance.
  3. Girdle: The girdle is the diamond's widest part and serves as the boundary between the crown and pavilion. In the radiant cut, the girdle can be faceted, bruted, or polished.
  4. Culet: This is the tiny facet at the very bottom of the pavilion. While some radiant cut diamonds might have a pointed or no culet, others may have a small faceted culet.
  5. Faceting Style:
    • The radiant cut employs a mixed faceting style. On the crown, you'll often find a combination of triangular and kite-shaped facets, contributing to its brilliant light effects.
    • The pavilion typically utilizes rectangular or sometimes triangular facets, a nod to the step-cut heritage seen in shapes like the emerald cut.
  6. Cropped Corners: A defining feature of the radiant cut is its cropped corners. While not a "facet" in the strictest sense, these corners differentiate the radiant from other square or rectangular cuts and help reduce the chances of chipping.

The radiant cut's unique blend of facets gives it a fiery sparkle. The meticulous placement of these facets is what enables the radiant cut diamond to display such a dazzling combination of brilliance and dispersion. Remember, though, there might be slight variations in the exact faceting pattern based on the cutter's preference and the specific diamond's characteristics.

Radiant cut light performance

Radiant cut diamonds are famous for their exceptional brilliance. Due to its numerous facets, the radiant cut captures and reflects light efficiently, while the interplay between white light reflections (brightness), colourful light dispersion (fire), and the pattern of light and dark areas (scintillation) makes the radiant cut irresistibly dazzling.

Development of the radiant cut

The radiant cut diamond is a relative newcomer to the world of diamond shapes, having been introduced in 1977 by the master diamond cutter, Henry Grossbard. Grossbard's passion for diamonds and his desire to combine the best elements of established cuts led to the creation of this new and distinctive shape.

Grossbard wanted to bridge the gap between the emerald and round brilliant cuts. He admired the emerald cut's elegant, linear facets but sought the intense brilliance and fire of the round brilliant. Combining these attributes was no small feat, as it required a profound understanding of how light interacts with diamond facets.

The initial challenge was incorporating the round brilliant's facet pattern into a rectangular or square shape. Grossbard meticulously crafted a design with 70 facets, maximising the diamond's internal reflection.

The radiant cut also introduced slightly cropped corners, distinguishing it from similar cuts like the princess or cushion. This not only provided a unique aesthetic but also reduced the risk of chipping.

Initially, the radiant cut catered to a niche market, with enthusiasts appreciating its modernity and difference. But as trends evolved, especially in the late 1990s and 2000s, the radiant cut gained more mainstream popularity. Also, due to its facet design, the radiant cut has become a preferred choice for fancy-coloured diamonds. The cut intensifies colour, making yellow or blue diamonds, for instance, appear even more vibrant. 

Choosing the Perfect Radiant Diamond

The Four Cs

The 'Four Cs' remain crucial for selecting any diamond, but there are specific considerations you should bear in mind for radiant cuts, in particular:

  • Carat: Radiant cuts tend to appear larger than other diamonds of the same carat weight due to their surface area.
  • Clarity: The radiant cut's facet pattern can hide some imperfections. However, due to its brilliant nature, significant inclusions might be visible.
  • Colour: Radiant cuts retain more colour, especially in their corners. For those sensitive to colour, consider a higher grade.
  • Cut: While the GIA doesn't provide a cut grade for radiant diamonds, it's important to consider the table and depth percentages (see below) and select a stone with very good or excellent symmetry and polish to ensure maximum brilliance.

Table and depth percentages

  • The table percentage is calculated by taking the width of the table facet (the flat, top surface of the diamond) and dividing it by the width of the diamond. For radiant cut diamonds, look for a table percentage in the range: 61% - 69%.
  • The depth percentage is calculated by dividing the diamond's depth (from the table to the culet) by its width. For radiant cut diamonds, look for a table percentage in the range: 61% - 67%.

Length-to-width ratios

As discussed, radiant cut diamonds range from those with very square proportions (length-to-width ratios of between 1 and 1.05) to very elongated proportions (1.3 is considered a typical length-to-width ratio, though some radiant cuts are much more elongated than this). There's no "right" shape, but its important to choose a stone with proportions that appeal to you and work well with the setting you have in mind

Girdle thickness and culet size

For radiant cut diamonds, as with other diamond shapes, the girdle thickness and culet size play important roles in the overall appearance and durability of the stone.

Girdle Thickness

  • Durability: A very thin girdle is more susceptible to chipping, especially given the radiant cut's cornered shape. Conversely, an extremely thick girdle can add unnecessary weight to the diamond, often hidden in a setting, which means you might end up paying for carat weight that isn't visible.
  • Appearance and Proportions: An overly thick girdle can also make a diamond appear smaller than its actual carat weight when viewed from the top. A balanced girdle thickness ensures the diamond's optimal brilliance and does not compromise the stone's proportions.
  • Grading Reports: Premium gemological labs like the GIA (Gemological Institute of America) will provide girdle thickness on their reports. It's generally mentioned as a range (e.g., "Thin to Slightly Thick"). For radiant cut diamonds, a range like "Medium" to "Slightly Thick" is generally safe, but this can vary based on personal preference and the specific diamond.

Culet Size

  • Visibility: A large culet might be visible when looking through the table of the diamond, appearing as a small, transparent circle or a dark point. This can distract from the diamond's overall appearance.
  • Symmetry: The culet should be centred and aligned with the table facet to maintain the symmetry and balance of the diamond. Off-centred culets can cause the diamond to appear tilted.
  • Size Recommendations: Ideally, for radiant cuts and many modern diamonds, the culet should be "None" to "Small" on a grading report. Larger culets were more common in antique cuts but are typically not desirable in modern radiant cuts.

Pros and cons of radiant cut diamonds

Radiant cut diamonds are wonderful stones, but like every diamond shape, they have some advantages and some disadvantages.

Versatility: Suitable for a wide range of jewellery designsInclusions Visibility: Although they hide imperfections better than some cuts, significant inclusions can still be discernible.
Brilliance: Offers a fiery sparkle that's hard to matchColour Retention: Radiant cuts retain more colour. If you're looking for a diamond that doesn't show colour then this is a drawback.
Unique Reflections: The blend of linear facets and brilliant sparkle creates a dance of light, making it stand out.
Pros and cons of radiant cut diamonds

Comparing the radiant cut to other diamond shapes

Radiant cut diamonds have some similarities to other popular diamond cuts but also some important differences, as set out below.

Radiant vs. princess cut

Square radiant cut vs. princess cut diamond
Square radiant cut vs. princess cut

Both radiants and princesses are brilliant cuts, and radiants are available in square proportions like princess cuts, but the radiant's cropped corners give it a distinctive appearance.

Radiant vs. emerald cut

radiant vs emerald cut edited
Rectangular radiant cut vs. emerald cut

While both are rectangular with cropped corners, the emerald is a step-cut diamond known for its clarity, while the radiant is a brilliant cut optimised for its sparkle. The same comparison can be made between the square radiant cut and the Asscher cut diamond.

Radiant vs. cushion cut

Radiant cut diamond vs. cushion cut diamond
Rectangular radiant cut vs. rectangular cushion cut

Both radiants and cushions come in a range of proportions from square to rectangular, but the cushion cut has a softer, more pillowy appearance, whereas the radiant cut has a more geometric look, with straight edges.

The best settings for radiant cut diamonds

Radiant cut diamonds are versatile and can look stunning in a variety of settings. Here we've set out some of the most popular styles of radiant cut engagement rings.

Solitaire radiant cut engagement rings

139 Giocoso RADIANT Yellow Pics 00004
Ingle & Rhode Giocoso engagement ring

This classic and timeless setting focuses solely on the diamond. With a radiant cut diamond, a solitaire setting allows the unique blend of brilliance and fire to stand out.

Radiant cut halo engagement rings

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Ingle & Rhode Capriccio engagement ring

A halo setting features a centre diamond surrounded by smaller diamonds or gemstones. This not only makes the main diamond appear larger but also adds extra sparkle. A halo setting can beautifully accentuate a radiant cut diamond.

Radiant cut engagement rings with diamond shoulders

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Ingle & Rhode Cadenza engagement ring

This beautiful style of ring has small round diamonds pavé set on the band, which, paired with a radiant cut centre diamond, offers a dazzling and luxurious look.

Radiant cut vintage engagement rings

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Ingle & Rhode Appassionate engagement ring

Vintage style radiant cut diamond rings combine a diamond halo with diamond shoulders, capturing the decadent luxury of the Edwardian era.


What is a radiant cut diamond?

A radiant cut diamond is a hybrid between a round and emerald cut, known for its cropped corners and brilliant facet pattern, offering both elegance and incredible sparkle.

How is the radiant cut different from other cuts?

It uniquely combines the linear facets of step cuts (like the emerald cut) with the brilliance of round cuts, resulting in a vibrant and fiery display of light.

Are radiant cut diamonds more expensive?

Prices vary depending on several factors, but radiant cut diamonds can sometimes be more affordable than popular cuts like the round brilliant due to less waste during the cutting process.

What length-to-width ratio is best for a radiant cut diamond?

It's subjective. A ratio of 1-1.05 creates a square appearance, anything more is considered rectangular. 1.3 and above is popular but the best ratio depends on personal preference.

How do radiant cuts compare in sparkle to other cuts?

Radiant cuts are among the most brilliant of diamond shapes, rivalling even the round brilliant cut in terms of light performance.

Do radiant cuts show colour or inclusions more?

Radiant cuts retain more colour, especially in their corners. While their brilliant facet pattern can hide some inclusions, significant flaws might still be visible.

What setting complements a radiant cut diamond best?

Radiant cuts are versatile and can be complemented by various settings, from solitaires and halos to vintage and modern designs.

Is the radiant cut prone to chipping?

While all diamonds can chip under the right conditions, the radiant cut's cropped corners make it less susceptible than diamond shapes with pointed corners, like the princess cut.

Are radiant cut diamonds popular for engagement rings?

Yes, they've gained popularity for those desiring a unique blend of shape and brilliance, making them a contemporary choice for engagement rings.

How does the radiant cut's fire compare to other shapes?

Due to its brilliant facet arrangement, the radiant cut exhibits a stunning amount of fire, outshining almost all other fancy shapes.


The radiant cut diamond, with its exceptional brilliance and contemporary design, offers a stunning alternative to traditional choices. Whether you're seeking a statement piece or a timeless treasure, the radiant cut is an exquisite choice that effortlessly merges tradition with modernity.

From its innovative origins in the 1970s to its contemporary status as a beloved choice for both clear and coloured diamonds, the radiant cut's journey is a testament to the enduring allure of craftsmanship and innovation. Please feel free to get in touch if you have any questions; we'd love to help!

Tim Ingle
Together with David Rhode, Tim created Ingle & Rhode to offer a better alternative to the traditional luxury brands. Since 2007, we’ve provided our customers with genuinely ethical engagement rings, wedding rings and fine jewellery – free from conflict diamonds, dirty gold and child labour. With more than 16 years experience in the jewellery industry, Tim has deep expertise in diamonds, gemstones and jewellery design and manufacturing.