Diamond shape is often the first decision couples make when selecting an engagement ring, and it is one of the most personal choices. Each shape has its own personality, from the classic elegance of the round brilliant to the vintage charm of the cushion cut. Understanding the characteristics, advantages, and considerations of each shape helps you find the one that resonates with your style and preferences.
While shape and cut are sometimes used interchangeably, they technically refer to different things. Shape describes the outline of the diamond when viewed from above, such as round, square, or oval. Cut refers to how well the diamond has been crafted, including its proportions, symmetry, and polish. Both factors significantly impact a diamond's beauty and value.
Round Brilliant: The Classic Choice
The round brilliant is the most popular diamond shape, accounting for approximately 75% of all diamonds sold. Its 58 facets are mathematically designed to maximise light return, producing exceptional brilliance, fire, and scintillation. The round brilliant has been refined over more than a century to achieve optimal light performance.
Round diamonds receive the only formal cut grade from GIA, making it easier to compare quality between stones. An Excellent or Ideal cut round brilliant will exhibit spectacular sparkle from any angle. The shape's symmetry also makes it the most forgiving of colour and clarity imperfections, as the faceting pattern disperses and masks minor characteristics.
Round brilliants command a premium over fancy shapes, typically 25-35% more expensive per carat. This premium reflects both their popularity and the greater rough diamond waste during cutting. If maximising carat weight is important, consider fancy shapes for better value.
Princess Cut: Modern and Brilliant
The princess cut is the second most popular shape, featuring a square or slightly rectangular outline with pointed corners. Created in the 1960s, it combines modern geometric lines with excellent brilliance rivalling the round. Princess cuts work beautifully in contemporary and minimalist settings.
The pointed corners of princess cuts require protective prong settings to prevent chipping. V-prongs or corner prongs are essential for this shape. Princess cuts also tend to show colour more readily than rounds, so consider staying with G or better colour grades if mounted in white metal.
Cushion Cut: Romantic and Vintage
Cushion cuts feature rounded corners and larger facets that create a soft, pillowy appearance. This antique shape predates the round brilliant and was the most popular diamond cut for over a century. Modern cushion cuts have been optimised for brilliance while retaining their romantic, vintage character.
Cushion cuts come in square and elongated rectangular versions, with length-to-width ratios varying from 1.00 (square) to 1.30 or more (elongated). The larger facets of cushion cuts display colour more prominently, making them excellent choices for fancy coloured diamonds or for showcasing a warm yellow gold setting.
Oval Cut: Elegant and Elongating
Oval diamonds combine the brilliance of a round with an elongated shape that can make fingers appear longer and more slender. The oval has become increasingly popular in recent years, offering a distinctive alternative to the round while maintaining excellent light performance.
Oval, marquise, and pear shapes can exhibit a "bow-tie" effect, a dark area across the centre caused by light leakage. The severity varies significantly between stones. Always view oval diamonds in person or through high-quality video to assess bow-tie before purchasing.
The ideal length-to-width ratio for ovals is generally considered 1.35 to 1.50, though personal preference varies. Ovals can also face up larger than rounds of equal carat weight due to their elongated shape, offering perceived size advantages.
Emerald Cut: Sophisticated Step-Cut
The emerald cut features a rectangular shape with cropped corners and long, linear facets arranged in parallel steps. Unlike brilliant cuts designed for sparkle, emerald cuts produce a "hall of mirrors" effect with dramatic flashes of light. This sophisticated style emphasises clarity and showcases the diamond's body colour.
Because emerald cuts have large, open facets with fewer places for inclusions to hide, clarity is particularly important. Most experts recommend VS1 clarity or better for emerald cuts, as SI grades may have visible inclusions. Similarly, colour is more apparent, so staying with H or better is advisable.
Pear Shape: Unique and Flattering
The pear shape, also called teardrop, combines a rounded end with a single point, creating a unique silhouette. Pear diamonds are particularly flattering when worn with the point facing the fingertip, as they elongate the finger. This distinctive shape works beautifully in both classic and contemporary settings.
Symmetry is crucial for pear shapes. The point should align perfectly with the apex of the rounded end, and both curved sides should be identical. Good symmetry requires careful examination, as even slight asymmetry is noticeable in this shape.
Marquise Cut: Dramatic and Historic
The marquise cut features an elongated shape with pointed ends at both tips, reportedly designed to resemble the smile of the Marquise de Pompadour. This shape has one of the largest face-up appearances of any diamond shape, making it excellent for maximising perceived size.
The pointed ends of marquise diamonds require protective settings, and like ovals, they can exhibit bow-tie effects. Marquise diamonds work particularly well in vintage-inspired settings and create a dramatic, eye-catching appearance.
Asscher Cut: Art Deco Glamour
The Asscher cut is a square step-cut with deeply cut corners that give it an almost octagonal appearance. Developed in 1902, this shape epitomises Art Deco elegance with its geometric precision and mesmerising depth. The Asscher's X-pattern when viewed from above is instantly recognisable.
Like emerald cuts, Asschers require high clarity grades due to their open faceting. Their architectural beauty makes them particularly suited to vintage and Art Deco inspired settings with geometric metalwork.
Radiant Cut: Brilliance Meets Geometry
The radiant cut combines the elegant shape of an emerald cut with the brilliance of a round, featuring cropped corners and brilliant-style faceting. This versatile shape offers the best of both worlds: geometric lines with exceptional sparkle. Radiants are available in square and rectangular proportions.
Radiant cuts are more forgiving of colour and clarity than step cuts, making them a practical choice for those who want a rectangular shape with maximum brilliance and value. Their trimmed corners also make them durable for daily wear.