Radiant Cut Diamonds - A Complete Guide

Radiant Cut Diamond

The radiant cut diamond is the first square cut (the second being the princess) to have a complete brilliant-cut facet pattern applied to both the crown and pavilion, creating a vibrant and lively square diamond. First popular in the 1980's, the cropped corner square shape of the radiant is a nice bridge between a cushion and a princess cut, and for that reason looks beautiful set with both rounded or square cornered diamonds.

In longer (more rectangular) radiant cut diamonds, a bow-tie effect is more likely (although not as common as in oval, marquise, and pear cuts), varying from near invisible to severe. The visibility of a bow-tie effect cannot be ascertained by reviewing the diamond certificate or dimensions, but only upon visual inspection. If you are interested in purchasing a radiant cut diamond, but would like to have it inspected first, please contact a diamond consultant, who can review diamonds on your behalf. chat online, or email [email protected].

The chart below serves as a general guideline for evaluating the cut of a radiant cut diamond.

EXCELLENT VERY GOOD GOOD FAIR POOR
Table %
61 - 69 57 - 60
or
70 - 72
54 - 56
or
73 - 74
51 - 53
or
75 - 79
< 51
or
> 79
Depth %
61 - 67 59 - 60.9
or
67.1 - 70
57 - 58.9
or
70.1 - 74
54 - 56.9
or
74.1 - 79
< 54
or
> 79
Girdle
Very Thin - Slightly Thick Very Thin
to
Thick
Very Thin
to
Very Thick
Ex. Thin
to
Ex. Thick
Culet
None Very Small Small Medium > Medium
Radiant Cut Diamond LW Ratios
Radiant Cut Diamond LW Ratios.

There are diverse preferences when it comes to shape in radiant cut diamonds, from a perfectly square 1.00 length to width ratio (any ratio of 1.05 or less will appear square to the naked eye), to a more traditional rectangle. The rectangular radiant cut is an excellent option for buyers who like the emerald cut shape, but want something with the brilliance of a round. The square radiant looks very similar to a princess cut, but with cropped corners. Once set, a square radiant and a princess look virtually identical, since the prongs cover the corners. Every Lumera Diamond includes precise measurements, as well as the length to width ratio, so you know the exact shape of the radiant cut diamond you are considering.

EXCELLENT VERY GOOD GOOD FAIR POOR
Square 1.00 - 1.03 1.04 - 1.05 1.06 - 1.08 > 1.08
Rectangle 1.20 - 1.30 1.15 - 1.19
or
1.31 - 1.35
1.10 - 1.14
or
1.36 - 1.40
1.08 - 1.09
or
1.41 - 1.50
< 1.08
or
> 1.50

Evaluating color in radiant cut diamonds is subjective. Keep in mind that many buyers may actually prefer the ever so slightly warmer colors of a G-H diamond over the cool colorlessness of a D-F diamond. In fact, most of the premium in price associated with radiant cut diamonds at the higher end of the color scale is driven by supply and demand; customers want the D-F color grades, and are willing to pay a premium to get them. In a world without diamond color grading, the price premium for higher grades would be much lower, as the actual differences in color are difficult to perceive.

The color chart below provides a general guide for evaluating color in radiant cut diamonds.

EXCELLENT VERY GOOD GOOD FAIR POOR
< .50 ct. D - G H - I J - K L - M > M
.51-1.0 ct. D - F G H - I J - K > K
1.0-2.0 ct. D - F G - H I - J > J
> 2.0 ct. D - F G H - I > I
Fluoro
None Faint - Med. Strong Very Strong

Like color, evaluating clarity in radiant cut diamonds is subjective. GIA provides excellent help with their clarity grades. Still, it is important to understand that each customer will have a unique standard for clarity. Some may be perfectly comfortable with an inclusion as long as they cannot easily see it. Others may insist on a more technically flawless appearance. Because of its brilliance, a radiant cut is more forgiving of inclusions than other square cuts (like asscher and emerald), especially when viewed with the naked eye. The clarity chart below provides a general guide for evaluating clarity in radiant cut diamonds.

EXCELLENT VERY GOOD GOOD FAIR POOR
< .50 ct. FL - VS2 SI1 - SI2 I1 I2 > I2
.51-1.0 ct. FL - VS1 VS2 - SI1 SI2 I1 - I2 > I2
1.0-2.0 ct. FL - VVS2 VS1 - VS2 SI1 - SI2 I1 > I1
> 2.0 ct. FL - VVS2 VS1 - VS2 SI1 SI2 > SI2

Questions about shape or other aspects of a diamond? Ask a diamond consultant for answers. A consultant will answer any questions you have, and if you like, search for diamonds on your behalf that match your criteria. chat online, or email [email protected].

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