Radiant Diamond
The radiant cut combines the elegant outline of an emerald cut with the brilliance of a round brilliant, featuring trimmed corners and a brilliant-style facet pattern. It offers the best of both worlds—geometric lines with exceptional sparkle.
Overview
The radiant cut was created by Henry Grossbard in 1977, designed specifically to combine the clean rectangular or square outline of a step cut with the light performance of a brilliant cut. The result is a shape that looks architectural from a distance but explodes with fire and scintillation when the light catches it—a combination no previous shape had achieved.
What distinguishes the radiant from the emerald cut is its faceting pattern. While the emerald cut uses long, parallel step facets that create a hall-of-mirrors effect, the radiant uses a complex brilliant-style facet arrangement beneath its table. This pattern breaks light into many small, intense flashes rather than broad, slow flashes. The practical benefit is that radiant cuts hide inclusions and body color far better than emerald cuts, allowing buyers to go lower on clarity and color grades without sacrificing visual quality.
The radiant's trimmed corners also offer a functional advantage: they make the stone more durable than sharp-cornered shapes like the princess cut, while still maintaining a geometric appearance. In the trade, radiants are priced 25-35% below round brilliants and represent one of the strongest value propositions in fancy shapes. They're available in both square (L/W ratio near 1.0) and rectangular (L/W ratio 1.20-1.40) proportions, and they work exceptionally well flanked by baguette or trapezoid side stones in three-stone settings.
Carat to Millimeter Chart
Approximate face-up dimensions for radiant diamonds at each carat weight.
| Carat Weight | Size (mm) |
|---|---|
| 0.25 ct | 3.5 x 3.5 |
| 0.5 ct | 4.5 x 4.5 |
| 0.75 ct | 5.2 x 5.2 |
| 1 ct | 5.7 x 5.7 |
| 1.25 ct | 6.1 x 6.1 |
| 1.5 ct | 6.5 x 6.5 |
| 2 ct | 7.2 x 7.2 |
| 3 ct | 8.1 x 8.1 |
| 4 ct | 8.9 x 8.9 |
| 5 ct | 9.5 x 9.5 |
Pros & Cons
Advantages
- +Combines geometric outline with brilliant-cut sparkle—unique among diamond shapes
- +Trimmed corners make it more durable than sharp-cornered shapes like princess
- +Excellent at hiding inclusions and body color due to brilliant faceting
- +25-35% less expensive than comparable round brilliants
- +Outstanding choice for fancy colored diamonds—the faceting intensifies color
- +Available in both square and rectangular proportions for versatility
Disadvantages
- -Can face up slightly smaller than other shapes of equal carat weight due to depth
- -No standardized cut grade from major labs—quality evaluation requires expertise
- -Less well-known than other shapes—some buyers may not recognize it
- -The complex facet pattern can sometimes produce a crushed ice appearance
- -Finding well-matched pairs for earrings can be challenging
Buying Tips
- •Decide between square (1.0-1.05 L/W) and rectangular (1.15-1.35 L/W) before shopping—they look very different
- •SI1 clarity is usually eye-clean in radiants thanks to the brilliant facet pattern
- •Color is well-masked—you can often drop to I or J color without visible warmth
- •If you're considering an emerald cut but want more sparkle, the radiant is your answer
- •For fancy colored diamonds (yellow, pink), the radiant is often the best shape to intensify color
- •Check depth percentage: aim for 61-67% for optimal light performance
- •Request video to verify even sparkle distribution—avoid stones with dead zones