Princess Diamond
The princess cut is a square modified brilliant with sharp, uncut corners that deliver exceptional brilliance in a geometric silhouette. It's the most popular non-round shape and offers outstanding value, costing significantly less per carat than rounds.
Is a princess diamond a good choice?
Princess diamonds are known for very high brilliance with 57 facets. They're popular for engagement rings and channel-set bands. Here are the trade-offs.
Why people love it
- +Exceptional brilliance that rivals round brilliants in light performance
- +25-35% less expensive than comparable rounds
- +Clean, modern geometric lines that appeal to contemporary tastes
- +One of the most efficient shapes to cut, which keeps prices down
- +Strong brilliance hides inclusions well, allowing lower clarity grades
Things to know
- −Sharp corners are vulnerable to chipping and must be protected by the setting
- −Shows color more than rounds, so consider higher color grades in white metals
- −Square shape can appear smaller face-up than elongated shapes of equal weight
- −No standardized cut grade from GIA. You need to evaluate proportions independently.
How big is a princess diamond? (MM to carat)
A 1-carat princess diamond measures approximately 5.5 x 5.5 mm. Here are the most common sizes from 0.25 ct to 5 ct.
| Carat Weight | Size (mm) |
|---|---|
| 0.25 ct | 3.3 x 3.3 mm |
| 0.33 ct | 3.6 x 3.6 mm |
| 0.5 ct | 4.2 x 4.2 mm |
| 0.75 ct | 4.9 x 4.9 mm |
| 1 ct | 5.5 x 5.5 mm |
| 1.25 ct | 5.9 x 5.9 mm |
| 1.5 ct | 6.3 x 6.3 mm |
| 2 ct | 7.0 x 7.0 mm |
| 2.5 ct | 7.5 x 7.5 mm |
| 3 ct | 7.9 x 7.9 mm |
| 4 ct | 8.7 x 8.7 mm |
| 5 ct | 9.3 x 9.3 mm |
View full princess size chart → with all sizes from melee to 5+ carats.
How to buy a princess diamond
- •Corner protection is non-negotiable. Always choose a setting with V-prongs or bezel at the corners.
- •Look for stones with chevron facets visible through the table. This indicates proper brilliant-style cutting.
- •Keep L/W ratio between 1.00 and 1.05 for a true square appearance; anything over 1.10 will look rectangular
- •Princess cuts can tolerate SI1-SI2 clarity better than step cuts because the brilliant faceting hides inclusions
- •Color tends to concentrate in corners. Stay at H or above in white metals.
- •Check the depth percentage: 65-75% is optimal; stones shallower than 65% may look glassy
- •Inspect corners carefully. Even small chips from handling at the wholesale level should be flagged.
What makes a princess diamond unique?
The princess cut was developed in the 1960s and 1970s, with the modern version typically attributed to Betzalel Ambar and Israel Itzkowitz in 1980. Its appeal lies in combining the brilliance of a round brilliant (thanks to its modified brilliant faceting pattern) with the clean, geometric lines of a square shape. The result is a diamond that sparkles intensely while offering a distinctly contemporary aesthetic.
From a rough utilization standpoint, the princess cut is one of the most efficient shapes, retaining up to 80% of the original rough crystal. This is because the square shape closely mirrors the octahedral crystal structure of diamond rough, minimizing waste. This efficiency translates directly to lower prices. Princess cuts typically cost 25-35% less than round brilliants of comparable quality. Two princess cuts can often be produced from a single octahedral crystal, further improving yield.
The most important consideration unique to princess cuts is corner protection. The four sharp, 90-degree corners are the thinnest parts of the stone and are vulnerable to chipping on impact. Every princess cut must be set with corner-protecting prongs or a channel/bezel setting. In the trade, princess cuts with chipped corners are a common repair issue, and jewelers should always counsel clients about this risk. Despite this drawback, the princess cut's combination of brilliance, modern geometry, and exceptional value keeps it firmly as the number-one alternative to the round brilliant.
How much does a princess diamond cost?
Princess 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 princess diamond price →Technical Specifications
- Facets
- 57
- Brilliance
- very high
- L:W Ratio
- 1.0:1 to 1.05:1 (square, most popular) or 1.05:1 to 1.20:1 (slightly rectangular)
Last updated: 2026-07-16
At a Glance
- Price vs Round
- 25-35% less than round brilliant
- Popularity
- Very popular (approximately 5-8% of engagement ring sales, second or third most popular shape)
- Sparkle
- very high
Best For
engagement ringschannel-set bandsthree-stone ringssolitaire settingsmodern designs
Setting Ideas
- Four-prong with V-prongs at all four corners (essential for chip protection)
- Channel setting. Ideal for side stones, eliminates corner exposure entirely.
- Bezel. Maximum corner protection with a sleek modern look.
- Halo. Softens the geometric look while adding perceived size.
- Three-stone with smaller princess or trillion side stones
- Invisible setting. Multiple princess cuts set together for a continuous diamond surface.