Diamond Shape Guide
While "Cut" refers to quality, "Shape" is all about personality. From the classic Round Brilliant to the vintage Cushion, explore how shape affects size, sparkle, and style.
Round Brilliant
Classic Round (1:1)
What is it?
The most popular diamond shape, representing over two-thirds of all diamonds sold. The Round Brilliant cut is designed to maximize light return, fire, and brilliance.
Expert Buying Tips
- Hides inclusions better than any other shape.
- Hides yellow color well, so you can go lower on Color grade (H-I).
- Most expensive per carat due to high rough diamond waste during cutting.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 5.2 mm | Modest & Elegant |
| 0.75 ct | 5.9 mm | Popular Value |
| 1.00 ct | 6.5 mm | The Gold Standard |
| 1.50 ct | 7.4 mm | Impactful |
| 2.00 ct | 8.2 mm | Statement Piece |
| 3.00 ct | 9.4 mm | Luxurious |
Oval
Classic Oval (1.40)
What is it?
An elongated version of the Round Brilliant. Ovals have become the top trending shape for engagement rings due to their ability to lengthen the finger.
Expert Buying Tips
- Look out for the 'Bow-Tie' effect (a dark shadow across the center).
- Appears larger than a round diamond of the same carat weight.
- Very forgiving of inclusions near the edges.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 6.0 x 4.0 mm | Delicate |
| 0.75 ct | 7.0 x 5.0 mm | Elegant |
| 1.00 ct | 7.7 x 5.7 mm | Popular Choice |
| 1.50 ct | 8.5 x 6.5 mm | Elongating |
| 2.00 ct | 9.5 x 7.0 mm | Showstopper |
| 3.00 ct | 11.5 x 8.0 mm | Celebrity Style |
Cushion
Square Cushion
What is it?
Known as the 'Pillow Cut', Cushion diamonds have rounded corners and larger facets to increase brilliance. They offer a vintage, romantic feel.
Expert Buying Tips
- Choose 'Chunky' facets for vintage looks or 'Crushed Ice' for modern sparkle.
- Retains color more than rounds, so stick to H color or better.
- Available in square (1:1) or elongated ratios.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 4.5 x 4.5 mm | Subtle |
| 0.75 ct | 5.0 x 5.0 mm | Vintage Feel |
| 1.00 ct | 5.5 x 5.5 mm | Classic Pillow |
| 1.50 ct | 6.5 x 6.5 mm | Substantial |
| 2.00 ct | 7.0 x 7.0 mm | Bold |
| 3.00 ct | 8.2 x 8.2 mm | Heirloom Quality |
Princess
Square
What is it?
The most popular square shape. It has pointed corners and is traditionally square-cut. Princess cuts offer intense sparkle and a modern geometric look.
Expert Buying Tips
- Corners are fragile; ensure the setting protects them (V-prongs).
- Look for a depth percentage between 68% and 75%.
- Offers the best price-per-carat value of all shapes.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 4.4 x 4.4 mm | Dainty |
| 0.75 ct | 4.9 x 4.9 mm | Sharp |
| 1.00 ct | 5.5 x 5.5 mm | Modern Classic |
| 1.50 ct | 6.4 x 6.4 mm | Eye Catching |
| 2.00 ct | 7.0 x 7.0 mm | Impressive |
| 3.00 ct | 8.0 x 8.0 mm | Grand |
Emerald
Classic Rectangle
What is it?
A step-cut diamond with long, parallel facets that create a 'Hall of Mirrors' effect. It emphasizes clarity over sparkle.
Expert Buying Tips
- Clarity is king. Inclusions are easily visible, so choose VS1 or better.
- Doesn't hide color well; stick to G color or higher.
- Perfect for Art Deco and vintage-inspired settings.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 5.0 x 3.5 mm | Understated |
| 0.75 ct | 6.0 x 4.0 mm | Refined |
| 1.00 ct | 6.5 x 5.0 mm | Sophisticated |
| 1.50 ct | 7.5 x 5.5 mm | Elegant |
| 2.00 ct | 8.5 x 6.5 mm | Stately |
| 3.00 ct | 9.5 x 7.0 mm | Regal |
Pear
Classic Teardrop
What is it?
Also known as the 'Teardrop', this shape combines the brilliance of a Round with the tapered point of a Marquise. It is unique and slimming.
Expert Buying Tips
- Always worn with the point facing the fingernail to elongate the hand.
- Protect the tip with a prong (v-prong) to prevent chipping.
- Check for symmetry—the rounded end should be perfectly semi-circular.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 6.5 x 4.0 mm | Sweet |
| 0.75 ct | 7.5 x 4.5 mm | Distinctive |
| 1.00 ct | 8.5 x 5.5 mm | Perfect Drop |
| 1.50 ct | 10.0 x 6.5 mm | Dramatic |
| 2.00 ct | 11.0 x 7.0 mm | Glamorous |
| 3.00 ct | 12.5 x 8.0 mm | Red Carpet |
Radiant
Elongated Radiant
What is it?
Combines the silhouette of an Emerald cut with the brilliance of a Round cut. It features cut corners and a faceted pavilion for maximum sparkle.
Expert Buying Tips
- Excellent option if you love the Emerald shape but want more sparkle.
- Very durable due to beveled corners (no sharp points).
- Available in square or rectangular ratios.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 5.0 x 4.5 mm | Compact Sparkle |
| 0.75 ct | 5.5 x 5.0 mm | Bright |
| 1.00 ct | 6.0 x 5.5 mm | Radiant |
| 1.50 ct | 7.0 x 6.0 mm | Flashy |
| 2.00 ct | 7.5 x 6.5 mm | Bold |
| 3.00 ct | 8.5 x 7.5 mm | High Impact |
Marquise
Slender & Long
What is it?
A football-shaped diamond with pointed ends. The Marquise has the largest surface area of any shape, making it look much larger than its actual carat weight.
Expert Buying Tips
- Maximizes carat weight—looks huge for the price.
- Requires symmetry; points must align perfectly.
- Watch for the 'Bow-Tie' effect in the center.
Ideal Length-to-Width Ratio
MM Size Chart
Approx. Dimensions| Carat | Dimensions (mm) | Look |
|---|---|---|
| 0.50 ct | 8.0 x 4.0 mm | Long |
| 0.75 ct | 9.0 x 4.5 mm | Slender |
| 1.00 ct | 10.0 x 5.0 mm | Striking |
| 1.50 ct | 11.5 x 5.5 mm | Dramatic |
| 2.00 ct | 13.0 x 6.5 mm | Regal |
| 3.00 ct | 15.0 x 7.5 mm | Imperial |
Still Undecided?
Our virtual gemologists can help you compare shapes and sizes in real-time.