Encyclopedia · Shapes & cuts
Radiant cut
By Diamond BrosUpdated 4 min read
What is a radiant cut diamond?
A radiant is a square or rectangular diamond with its corners cut off, giving an eight-sided outline. GIA describes it as having step-cut facets on the crown and brilliant-cut facets on the pavilion, and says it has 70 facets that produce a "crushed ice" look. The result is the straight-edged shape of an emerald cut with more of the glitter of a round brilliant.
Because GIA gives an overall cut grade only to round brilliants, a radiant has none from GIA. Its report lists polish and symmetry, and the rest is judged by eye.
Who invented the radiant cut, and when?
Henry Grossbard, a diamond cutter born in Vienna, is credited with the radiant. He patented the style as "The Original Radiant Cut" (per GIA). Accounts differ on the date: GIA places the patent in the late 1970s, while JCK's obituary of Grossbard says he devised it in 1976 and that it received one of the first patents ever issued for a diamond cut. Mid-to-late 1970s is the safe way to say it.
In that obituary Grossbard says cutters usually cut a stone to reduce its body colour, but that with radiants you can also increase the colour of fancy-colour stones. JCK adds that Van Cleef & Arpels' advertising of the cut was crucial to its success. The patent has since expired, so others can cut the style and a radiant today may not be a Grossbard original.
Why do people choose radiant over emerald or Asscher?
The main reasons are forgiveness and durability. The brilliant faceting helps mask inclusions and warm colour, making the radiant more forgiving than step cuts such as the emerald, and the cropped corners help prevent chipping, which suits everyday wear. Radiants also tend to cost less per carat than round brilliants while offering similar sparkle (as of 2026). Compare actual quotes, since prices vary by stone.
The flip side is that the faceting can change how colour looks. It can make a stone appear lighter or darker from above, and coloured diamonds are sometimes recut as radiants to improve their face-up colour. See fancy coloured diamonds for that side of the market.
| Feature | Radiant | Asscher |
|---|---|---|
| Outline | Square or rectangular, cut corners | Square, bevelled corners |
| Faceting | Step crown, brilliant pavilion, about 70 facets | Step-cut facets, high crown, small table |
| Look | Crushed-ice sparkle | Hall-of-mirrors effect, often an X face-up |
| Flaws | Helps mask inclusions and warm colour | Tends to show inclusions and body colour more readily than brilliant cuts |
What should you check on a radiant, and how do you set it?
GIA points to three things: a centred culet, parallel sides and even corners that are neither too wide nor too narrow. Length-to-width also sets the shape: a ratio near 1:1 gives a square radiant, and a larger number gives a rectangle, which has a lengthening effect on the finger. Pick the proportion you like by eye.
For mounting, GIA lists prong settings in solitaire designs, side-stone designs and halo settings as common mountings for a radiant. Look at colour and clarity in the stone you will actually buy, not just the grade letters.
Is a radiant cut right for you?
It suits a buyer who wants a rectangular or square outline, wants some lenience on clarity or warmer colour, and prefers lively sparkle. It may disappoint someone who wants the quieter look of a step cut such as the emerald or Asscher cut.
The diamond shapes guide lays out the alternatives. You can browse the engagement ring collection, or bring a radiant idea to the design studio. To see stones in person, visit a Diamond Bros showroom; custom engagement rings are also available there.
Key takeaways
- A radiant is a square or rectangular diamond with cut corners and about 70 facets.
- Henry Grossbard developed it in the 1970s; accounts date it to 1976 or the late 1970s.
- It is more forgiving of inclusions and warm colour than step cuts, and the corners resist chipping.
- It has no GIA cut grade, so check the centred culet, parallel sides and even corners yourself.
- The faceting can shift how colour looks, so judge the actual stone.
Common questions
What is the difference between a radiant cut and an emerald cut?
Both are rectangular with cut corners. An emerald cut uses step facets all over, which gives long, clean lines and shows flaws more readily than a radiant does. A radiant uses step facets on the crown and brilliant facets on the pavilion, which creates a crushed-ice sparkle and helps mask inclusions and warm colour.
Is a radiant cut good for an engagement ring?
Yes, for the right buyer. The cropped corners help prevent chipping and the faceting is more forgiving of inclusions than an emerald cut's, both useful in a ring worn daily. Prong settings, solitaires, side-stone designs and halos all suit it. As with any fancy shape, view the stone in person to judge its corners and symmetry.
Does a radiant cut hide colour?
To a degree. Its faceting helps mask warm colours, but the faceting can also make colour look lighter or darker when viewed from above. That is why coloured diamonds are sometimes recut into radiants. Do not assume a lower colour grade will disappear; compare stones side by side under the same light.
Is a radiant cut cheaper than a round diamond?
Radiants tend to cost less per carat than round brilliants while offering similar sparkle. Prices depend on the individual stone's weight, colour and clarity, and on the market at the time, so ask for written quotes on two or three radiants and a round of similar weight rather than assuming.
Sources
- Selecting a radiant cut diamondGIA · 4cs.gia.edu
- Guide to diamond shapes for engagement ringsGIA · 4cs.gia.edu
- Henry Grossbard, 79, inventor of the radiant cutJCK · jckonline.com
- Diamond cut: GIA's cut grading systemGIA · 4cs.gia.edu
Related guides
- Diamond shapes: every shape comparedCompare ten diamond shapes by apparent size, sparkle, length-to-width ratio and weak points, then match a shape to your hand and setting.
- How to choose an engagement ring: a step-by-step guideA step-by-step way to choose an engagement ring: set the budget, then the stone, shape, setting, metal, diamond qualities, ring size and timing, with the trade-offs at each stage.
Related terms
- Emerald cutAn emerald cut is a rectangular diamond with cropped corners and rows of long, flat facets stepped down like a staircase.
- Asscher cutAn Asscher cut is a square step-cut diamond with cut (bevelled) corners, a high crown and a small table.
- Round brilliant cutA round brilliant cut is a circular diamond with 57 or 58 facets, arranged to send as much light as possible back to your eye.
- Princess cutA princess cut is a square diamond cut in a modified brilliant style, so it keeps a lively, sparkly face despite its sharp corners.
- Diamond cut gradeA diamond cut grade is a laboratory's rating of how well a polished diamond's proportions and finish handle light.
- Prong settingA prong setting holds a stone with narrow metal supports, called prongs, that grip it at the edge and leave most of the stone exposed to light.
- Halo settingA halo setting surrounds a centre stone with a ring of smaller accent stones.
- Fancy coloured diamondsA fancy coloured diamond has a body colour outside the normal range used for white diamonds (the D to Z colour scale): either more colour than the Z reference stone, or a colour other than yellow, brown or grey, such as blue, pink or green.
In the shop
Talk it through with a jeweller
Bring your questions to a private appointment at any of our 3 showrooms, in Mississauga or Brampton, or meet by video. Nothing is ordered until the design, the stone and the price are confirmed with you.