Comprehensive Buying Guide: Oval Cut Diamond Rings

Learn everything you need to know about buying an oval cut diamond ring.

History of Oval Cut Diamonds

The oval cut diamond has a rich history that spans centuries, reflecting both advances in gem-cutting technology and evolving aesthetic preferences. The idea of shaping gemstones into oval forms can be traced back to ancient times, though these early cuts were rudimentary and lacked the precision of modern techniques. During the Renaissance, advances in gem-cutting began to allow for more sophisticated shapes, including ovals, but these were still relatively uncommon compared to other shapes like the rose cut or the table cut. The modern oval cut diamond as we know it was developed in the mid-20th century. A major milestone in the history of the oval cut came in 1957 when Russian-born diamond cutter Lazare Kaplan, a relative of the famed Asscher family, introduced the modern oval cut. Kaplan's innovation was driven by his desire to create a diamond cut that would maximize the brilliance and fire of the stone while providing an elegant, elongated shape. Kaplan’s oval cut features 56-58 facets, similar to the round brilliant cut, which allows it to retain a high level of brilliance and fire. Advances in diamond cutting technology have continued to refine the oval cut, allowing for greater precision and consistency in achieving the ideal proportions and symmetry.

Popularity of Oval Cut Diamonds

Oval cut diamond rings are popular due to their elegant and flattering shape, enhanced brilliance, versatility in settings and celebrity endorsements. The oval cut diamond combines the brilliance of the round cut, while the elongated shape allows for excellent light reflection. An oval cut diamond can be set in both modern and vintage settings. The unique shape also allows the diamond to be set east-west providing even more ways customize the setting versus a round diamond.

Rarity also makes oval cut diamonds popular with luxury buyers. Oval cut diamonds over 3 carats in VS clarity or better and G color or better make up less than 1% of the diamond market. Round brilliant diamonds account for 75% of diamonds sold and only 1% of diamonds are over 2 carats.

The 4 Cs: Carat, Clarity, Color, and Cut

Oval cut diamonds typically have 56-58 facets and the elongated shape makes the diamond appear larger than a round diamond.

Carat: As a luxury seller of diamonds, Sotheby's generally carries oval cut diamonds that are 3 carats and above. Sotheby's sells some smaller oval cut diamonds but these are either colored diamonds or very high quality diamonds that are classified as colorless and in the flawless/internally flawless clarity grade.
Clarity: Sotheby's recommends a clarity grade of VS1 or higher for oval cut diamonds. Oval diamonds can exhibit a bow tie effect, dark area across the center of the diamond. A well cut stone with higher clarity will have less noticeable bow-tie.
Color: Oval diamonds show color more easily than round diamonds so we recommend a G color or better.
Cut: A common ratio for oval diamonds is 1.30 and 1.50. A ratio of 1.35-1.45 is often considered ideal for a balanced appearance.

Type I and Type II Diamonds

About 95% of diamonds are Type Ia and contain trace amount of nitrogen. Most engagement rings and other diamond jewelry are made from Type Ia diamonds. Type Ib diamonds are often associated with intense canary yellow diamonds and are often used for jewelry. Type II diamonds are much rarer than Type I diamonds and have fewer inclusions and higher clarity than the more common Type I diamonds.

Type IIa diamonds are the purest form of diamonds with no measurable nitrogen or boron impurities. These diamonds are often colorless but can also be found in rare colors like pink, brown or blue. These are extremely rare and comprise less and 2% of all mined diamonds. These diamonds are formed under high-pressure and high-temperature conditions which can give the diamond higher clarity and brilliance. Sotheby's sold a Type IIa Oval Brilliant Cut diamond weighing 55.55 carats for about $5.9 million in 2024.

Type IIb diamonds contain boron which give them blue or grayish-blue color. Unlike other diamonds, Type IIb are semiconductors and can conduct electricity and are even rarer than Type IIa diamonds. The Hope Diamond is an example of a famous Type IIb diamond.

Fancy Colored Oval Cut Diamond Rings

The elongated shape of the oval cut can enhance the color of fancy colored diamonds, making it a favored choice for colored stones as well. Oval cut colored diamonds are significantly more expensive than similar size and quality white diamond due to rarity in the market. Sotheby's sold a fancy intense orangy pink oval modified brilliant cut weighing 4.76 carats for 1.1 million CHF and a fancy yellow oval cut diamond weighing 33.03 carats for $610,000 in 2023.

Celebrity Oval Cut Diamond Rings

Many celebrities have chosen oval cut diamond engagement rings. Blake Lively's engagement ring from Ryan Reynolds is a 12-carat oval cut pink diamond set in a rose gold pave band. Hailey Baldwin Bieber has received two oval cut diamond rings from Justin Bieber. Her original engagement ring featured an oval diamond estimated between 6-10 carats and her recent upgrade features an estimated 18-carat oval cut diamond. Selma Hayek received a 5-carat oval cut diamond engagement ring from Francois-Henri Pinault. Nicola Peltz's second engagement ring from Brooklyn Beckham features an oval cut diamond estimated to be between 6-8 carats. Kourtney Kardashian received a 10 carat oval cut engagement ring from Travis Barker.

Buying an Oval Cut Diamond Ring at Sotheby's

Sotheby's sells natural oval cut diamond rings on its marketplace, available for immediate shipping. Prices start at around $40,000 for a 3 carat oval cut diamond that is VS clarity and G color. This price can vary depending on the cut, brand and provenance. Along with high quality unsigned diamond rings VS clarity and G color or better, Sotheby's also sells oval cut diamond rings from top luxury brands including Harry Winston, Tiffany, Cartier and more. Sotheby's also sells rare and impressive oval cut diamond rings at auctions in New York, London, Switzerland, Paris and Hong Kong. You can also contact a Client Advisor in New York or Bucherer in Zurich to learn more about Sotheby's diamond engagement rings. In addition to the available oval cut rings listed on marketplace or available at auction, Sotheby's is also able to source an oval cut diamond engagement ring from its global supplier network. Browse our curated selection online and reach out to a Salon associate to schedule a viewing.