

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.
Is a radiant diamond a good choice?
Radiant diamonds are known for very high brilliance with 70 facets. They're popular for engagement rings and three-stone rings. Here are the trade-offs.
Why people love it
- +Combines a 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 because the faceting intensifies color
Things to know
- −Can face up slightly smaller than other shapes of equal carat weight due to depth
- −No standardized cut grade from major labs, so 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
How big is a radiant diamond? (MM to carat)
A 1-carat radiant diamond measures approximately 5.7 x 5.7 mm. Here are the most common sizes from 0.25 ct to 5 ct.
| Carat Weight | Size (mm) |
|---|---|
| 0.25 ct | 3.5 x 3.5 mm |
| 0.33 ct | 3.8 x 3.8 mm |
| 0.5 ct | 4.5 x 4.5 mm |
| 0.75 ct | 5.2 x 5.2 mm |
| 1 ct | 5.7 x 5.7 mm |
| 1.25 ct | 6.1 x 6.1 mm |
| 1.5 ct | 6.5 x 6.5 mm |
| 2 ct | 7.2 x 7.2 mm |
| 2.5 ct | 7.6 x 7.6 mm |
| 3 ct | 8.1 x 8.1 mm |
| 4 ct | 8.9 x 8.9 mm |
| 5 ct | 9.5 x 9.5 mm |
View full radiant size chart → with all sizes from melee to 5+ carats.
How to buy a radiant diamond
- •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
What makes a radiant diamond unique?
How much does a radiant diamond cost?
Radiant diamonds are priced at 25-35% less than round brilliant. Price depends on carat weight, color, clarity, and cut quality. For a personalized estimate, use our diamond price estimator.
Estimate radiant diamond price →Technical Specifications
- Facets
- 70
- Brilliance
- very high
- L:W Ratio
- 1.0:1 to 1.05:1 (square) or 1.15:1 to 1.40:1 (rectangular)
Last updated: 2026-07-16
At a Glance
- Price vs Round
- 25-35% less than round brilliant
- Popularity
- Moderate popularity (approximately 3-5% of engagement ring sales, growing)
- Sparkle
- very high
Best For
Setting Ideas
- Three-stone with baguette or trapezoid side stones (the quintessential radiant setting)
- Solitaire with four prongs, simple and effective
- Halo that adds perceived size while highlighting the geometric outline
- Bezel setting that complements the trimmed corners and protects the stone
- Channel-set band. Radiants sit well side by side in channel settings
- Cathedral setting. The elevated profile showcases the stone beautifully