Radiant cut diamonds are a popular choice for fine jewellery. An engagement ring would be a good sample, as well as a diamond necklace and also diamond earrings. But what really is a radiant cut diamond?

A radiant cut diamond is a rectangular or square-shaped diamond with trimmed corners. It is known for its brilliance and fire due to its large facets. The radiant cut was developed in the 1970s and combined the best features of the round and emerald cuts. The length-to-width ratio of the radiant cut diamond is usually between 1.00 and 1.05, which means that the diamond is slightly longer than it is wide. 

If you are considering a radiant cut diamond for your engagement ring or other pieces of jewellery, be sure to work with a reputable jeweller to find the perfect stone for you.

radian cut pink diamond

Properties of Radiant Cut Diamond

Quality of Radiant Cut Diamond

For both the pavilion and crown, radiant diamonds have modified-brilliant cut facet patterns, which are responsible for their high level of brilliance (light reflected back to the eye). A careful eye must be used when considering stones for purchase as cut plays a vital role in determining the beauty of any diamond, especially the radiant diamond.

Round brilliant cut diamonds are the only ones graded by the Gemological Institute of America for cut quality. This independent, non-profit scientific organisation works with universities and other organisations to promote and advance gemology in the United States and worldwide. It is not possible to determine the true appearance of a radiant cut diamond from a GIA certificate because GIA certificates do not include a cut grade. Ideally, you should compare loose radiant diamonds with the eyes of a professional when comparing loose diamonds. 


Radiant Cut Diamonds are graded by many labs, but only a few are trustworthy. Our experience has shown that GIA and AGS grade diamonds consistently and accurately, while other labs create dangerous inconsistencies. GIA or AGS certificates should be used only when considering Radiants. 

Before making a decision on any diamond, you should review it thoroughly in addition to receiving a lab report. A diamond's appearance is not indicated in a lab report. It is only you and an expert who can determine true beauty and appearance.

Length to Width Ratio

The length-to-width ratio of a diamond is a measure of the proportions between the diamond's true shape (i.e. square vs rectangular) and is calculated by dividing the diamond's length by its width. It is entirely up to you to determine what ratio is most pleasing to you when it comes to your radiant diamond. For radiant length-to-width ratios, the lower end indicates a square shape, while the upper end indicates a more rectangular shape. For a more rectangular shape, the length-to-width ratio can be as high as 2.0.

radian cut diamond earrings

Clarity of Radiant Cut Diamond

It is the cleanness of a diamond that determines the diamond's clarity. This indicates whether the stone is free of inclusions and blemishes. Based on the GIA's scale, Clarity is rated as follows:

VVS1(Very Very Small Inclusions) and VVS2 appear very similar, so it is nearly impossible to distinguish the difference between the two grades with the naked eye. A radiant also has many angles and facets, giving it an appearance similar to crushed ice. In this regard, radiant cut diamonds are generally recommended in S1(Small Inclusions) or S2 Clarity to ensure you won't be paying for something useless. Having an expert check for inclusions and blemishes is more important than anything else since it can affect the price of the radiant cut diamond negatively.

Colour of Radiant Cut Diamond

Additionally, Radiant Cuts should be reviewed for their Colour. Colour rankings are based on a scale of D to Z as determined by the GIA. Diamonds with a D grade are the clearest, colourless diamonds; diamonds with a Z grade have a yellow or brown tint that is noticeable. In comparison to other diamond shapes, Radiant Cuts exhibit less colour variation. 


Radiant cut diamonds are a type of diamond that is known for their unique shape and brilliant sparkle. This type of diamond is also one of the most popular choices for engagement rings and other fine jewellery.

If you are looking for a truly unique and beautiful diamond, then you should definitely consider a radiant cut diamond.

radian cut yellow diamond ring


What does GIA or the Gemological Institute of America do?

Gemological Institute of America, or GIA, is a nonprofit diamond grading and gemstone identification institute. Founded in 1931, GIA is headquartered in Carlsbad, California and operates 13 offices around the world.

GIA's mission is to ensure public trust in diamonds and gemstones by providing the world's most respected gemological credentials and impartial research findings. The institute offers a variety of services, such as diamond grading, coloured stone identification, and pearl identification.

This institute is the world's leading authority on diamonds and gemstones. The institute's gemologists are highly trained experts who use state-of-the-art equipment to evaluate diamonds and gemstones. GIA's diamond grading system is universally recognised as the industry standard.

Why are radiant diamonds more expensive?

Radiant diamonds are more expensive because they have a unique cut that makes them extra sparkly. The radiant cut was invented in 1977, and it has 62 facets. That's more than any other diamond cut. The extra facets help to reflect light better, making the diamond appear brighter. Radiant diamonds also tend to be larger than other diamonds, which adds to their cost.