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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 diamond shape

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

1.00 - 1.01is the "sweet spot"
Square / ShortElongated / Skinny
Shop Round Brilliant Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct5.2 mmModest & Elegant
0.75 ct5.9 mmPopular Value
1.00 ct6.5 mmThe Gold Standard
1.50 ct7.4 mmImpactful
2.00 ct8.2 mmStatement Piece
3.00 ct9.4 mmLuxurious
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Oval diamond shape

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

1.30 - 1.50is the "sweet spot"
Square / ShortElongated / Skinny
Shop Oval Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct6.0 x 4.0 mmDelicate
0.75 ct7.0 x 5.0 mmElegant
1.00 ct7.7 x 5.7 mmPopular Choice
1.50 ct8.5 x 6.5 mmElongating
2.00 ct9.5 x 7.0 mmShowstopper
3.00 ct11.5 x 8.0 mmCelebrity Style
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Cushion diamond shape

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

1.00 - 1.05is the "sweet spot"
Square / ShortElongated / Skinny
Shop Cushion Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct4.5 x 4.5 mmSubtle
0.75 ct5.0 x 5.0 mmVintage Feel
1.00 ct5.5 x 5.5 mmClassic Pillow
1.50 ct6.5 x 6.5 mmSubstantial
2.00 ct7.0 x 7.0 mmBold
3.00 ct8.2 x 8.2 mmHeirloom Quality
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Princess diamond shape

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

1.00 - 1.05is the "sweet spot"
Square / ShortElongated / Skinny
Shop Princess Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct4.4 x 4.4 mmDainty
0.75 ct4.9 x 4.9 mmSharp
1.00 ct5.5 x 5.5 mmModern Classic
1.50 ct6.4 x 6.4 mmEye Catching
2.00 ct7.0 x 7.0 mmImpressive
3.00 ct8.0 x 8.0 mmGrand
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Emerald diamond shape

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

1.30 - 1.50is the "sweet spot"
Square / ShortElongated / Skinny
Shop Emerald Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct5.0 x 3.5 mmUnderstated
0.75 ct6.0 x 4.0 mmRefined
1.00 ct6.5 x 5.0 mmSophisticated
1.50 ct7.5 x 5.5 mmElegant
2.00 ct8.5 x 6.5 mmStately
3.00 ct9.5 x 7.0 mmRegal
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Pear diamond shape

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

1.45 - 1.70is the "sweet spot"
Square / ShortElongated / Skinny
Shop Pear Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct6.5 x 4.0 mmSweet
0.75 ct7.5 x 4.5 mmDistinctive
1.00 ct8.5 x 5.5 mmPerfect Drop
1.50 ct10.0 x 6.5 mmDramatic
2.00 ct11.0 x 7.0 mmGlamorous
3.00 ct12.5 x 8.0 mmRed Carpet
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Radiant diamond shape

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

1.20 - 1.30is the "sweet spot"
Square / ShortElongated / Skinny
Shop Radiant Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct5.0 x 4.5 mmCompact Sparkle
0.75 ct5.5 x 5.0 mmBright
1.00 ct6.0 x 5.5 mmRadiant
1.50 ct7.0 x 6.0 mmFlashy
2.00 ct7.5 x 6.5 mmBold
3.00 ct8.5 x 7.5 mmHigh Impact
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct
Marquise diamond shape

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

1.75 - 2.15is the "sweet spot"
Square / ShortElongated / Skinny
Shop Marquise Diamonds

MM Size Chart

Approx. Dimensions
CaratDimensions (mm)Look
0.50 ct8.0 x 4.0 mmLong
0.75 ct9.0 x 4.5 mmSlender
1.00 ct10.0 x 5.0 mmStriking
1.50 ct11.5 x 5.5 mmDramatic
2.00 ct13.0 x 6.5 mmRegal
3.00 ct15.0 x 7.5 mmImperial
*Dimensions are approximate for "Ideal" cut proportions. Actual mm size varies by depth and cut quality.
0.50 ct
0.75 ct
1.00 ct
1.50 ct

Still Undecided?

Our virtual gemologists can help you compare shapes and sizes in real-time.

Guide to Diamond Shapes

The shape of a diamond is one of the most personal choices in fine jewelry. It influences not only the overall appearance of the stone but also how light interacts with its facets, how large it appears on the finger, and how it complements different ring settings and personal styles. Whether you prefer timeless classics or modern silhouettes, there is a diamond shape to suit every taste.

Popular Diamond Shapes

  • Round Brilliant — The most popular diamond shape in the world. Its 58 precisely angled facets maximize light return, producing unmatched brilliance, fire, and sparkle. Ideal for any setting style.
  • Oval — An elegant elongated shape that creates the illusion of greater size per carat. Its curved form flatters the finger and offers exceptional brilliance similar to the round brilliant.
  • Princess — A modern square cut with pointed corners and exceptional brilliance. The princess is the second most popular shape and pairs beautifully with solitaire and halo settings.
  • Cushion — A romantic square or rectangular shape with rounded corners and large facets that emphasize clarity and produce a soft, pillow-like appearance. Available in square and elongated proportions.
  • Emerald — A step-cut rectangle with cropped corners that highlights the diamond's clarity and color. Its hall-of-mirrors effect creates a sophisticated, understated elegance favored in vintage and modern settings alike.
  • Pear — A graceful teardrop silhouette combining the round and marquise shapes. When worn with the point toward the fingertip, it creates a slenderizing effect and distinctive style.
  • Marquise — An elongated shape with pointed ends that maximizes carat weight, making the diamond appear larger than its actual weight. Its dramatic profile is bold and eye-catching.
  • Radiant — A versatile rectangular or square shape with trimmed corners and brilliant-cut facets. It combines the elegance of the emerald cut with the sparkle of the round, and pairs well with both round and square side stones.
  • Asscher — A square step-cut with deeply trimmed corners, producing a distinctive windmill pattern when viewed from above. It has an art deco aesthetic and emphasizes clarity.
  • Heart — The ultimate romantic diamond shape, symbolizing love and commitment. Its symmetry is critical to its beauty, and it is most impactful in larger carat weights where the shape is clearly visible.

Shop by Shape

Browse engagement rings in every diamond shape