For many, the appearance of a radiant cut diamond is an example of perfectly balanced beauty; the brilliant-cut facet patterning gives a sparkle to outshine a princess cut and this is combined with the vintage-softness of a cushion cut. Despite this common comparison the designer, Henry Grossbard, created the radiant cut in 1977 to combine the key elements from the round brilliant and emerald cut diamonds.   

Whichever stunning hybrid the radiant cut most resembles, its popularity in the 1980’s has not subsided and this cut continues to be popular with buyers looking for something a little unusual with the intense radiance and sparkle that we have come to expect from our diamonds. Uniting features from both step cuts and brilliant cuts, it is the perfect choice for those who want to have it all.

The cut features a total of 70 facets, creating a brilliance that is surpassed only by the round brilliant. The soft bevelled corners not only ensure durability, but give an unusual softness to the silhouette of the stone. It is the first cut to have brilliant-facet patterning applied to both the crown and the pavilion: radiant by name and certainly radiant by nature.

James Allen and Blue Nile have great selections of radiant cut diamonds to choose from, however if you’re considering a more classic cut like a princess or round then consider Whiteflash, their A CUT ABOVE® Diamonds are the best quality cut available online.


The GIA do not offer a cut grade for radiant cut diamonds, however below is a general guideline for finding the best radiant cut possible.

Table %61 - 6957 - 60 or 70 - 7254 - 56 or 73 - 7451 - 53 or 75 - 79< 51 or   > 79
Depth %61 - 6759 - 60.9 or 67.1 - 7057 - 58.9 or 70.1 - 7454 - 56.9 or 74.1 - 79< 54 or   > 79
GirdleVery Thin - Slightly ThickVery Thin to ThickVery Thin to ThickVery Thin to Thick
CuletNoneVery SmallSmallMedium> Medium

As cut quality has the greatest impact on the quality and appearance of the diamond, it is important to consider all factors regarding the cut.

A radiant cut is typically rectangular or square in shape. To gain a more in-depth understanding of the aesthetics of the diamond you are looking at, you may consider calculating the length to width ratio.

This ratio is calculated by dividing the diamond length by its width. The ratio will indicate how proportionate the stone is for its intended shape.

Image courtesy of Blue Nile

The most popular length to width ratios fall between 1.15 to 1.35; a radiant cut with a ratio of 1.15 is much closer to a square shape and a diamond of 1.35 gives a more elongated, rectangular shape. The best ratio for a square radiant cut is between 1.00 and 1.03, while the best ratios for a rectangular radiant cut are between 1.20 to 1.30.

Choosing a ratio will be decided entirely by your preference, so familiarise yourself with a range of ratios and decide which is most suitable for your jewelry.  


To ensure the best-looking diamond possible, it is important to choose a color grading that will deliver a colorless dazzle to compliment the radiance of this cut.

Despite its brilliance, the radiant cut does not conceal color as well as other cuts, such as the round brilliant. For this reason, I recommend an H in color.

At this grade, your diamond will fall into the ‘near-colorless’ bracket on the GIA color grade scale. An H grading is the best balance between price and beauty, with the stone appearing colorless to the eye.

If you are selecting a warm setting for your jewelry (such as yellow or rose gold) an I or J grade would still appear colorless against the setting.

Color is perhaps the most subjective of the Four C’s, so for those who are naturally sensitive to color in a diamond, take a look at stones with a color grading of G. Anything above this would place the diamond in the D-F color category (colorless) where you will see huge jumps in price with imperceptible visual difference.

A radiant cut diamond looks beautiful when set with side stones; the merge of brilliant and step cut means a radiant diamond can be placed next to almost any cut of side stone and look beautiful. If you choose to set your diamond with side stones, be sure that they are no more than one color grade away from your central stone.


Although a radiant cut incorporates elements from the less forgiving step cuts, the multiples facets give a ‘crushed ice’ effect to the stone, making it excellent at concealing inclusions.

I would recommend beginning your search at an SI1 clarity; at this grade you will find well priced diamonds that can appear eye-clear. This beautiful SI1 1.01ct radiant cut from James Allen presents a 1.33 ratio giving it a balanced rectangular silhouette. It also displays the crushed ice look and at SI1 clarity, is beautifully eye clean.

As always, seeing is believing when it comes to clarity, so be sure to view the diamond through high-res 360 imaging, offered by James Allen and Blue Nile. Positioning is everything when it comes to inclusions and taking the time to look for an eye-clean SI1 stone can save you thousands of dollars.

For larger stones (around 2.00ct and above) you may consider extending your search up one grade to a VS2 as inclusions can often be easier to spot in larger diamonds.

Eye-clean is the golden rule when it comes to inclusions.  

The Final Word

An ethereal hybrid, a radiance that turns heads from across the room and a diamond cut so flexible it is a star in any setting; the radiant cut really can do it all.

To get the most from this stand-out stone, it is essential to follow the above guidelines on quality and opt for an internationally recognised certification (either AGS or GIA), for only these will ensure you are getting a diamond of the highest quality.

I recommend Blue Nile and James Allen for their impressive inventory of loose diamonds and their exceptional high-res imaging. I also suggest Whiteflash for their unrivalled portfolio of high quality designer engagement ring settings, however they specialise more in princess and round cut diamonds.

The sparkle of a round brilliant and the cool edge of a step-cut; the boldest of buyers will choose a radiant cut.