Diamond fundamentals
Diamonds are among the most valuable and rare products of the natural world.
Understanding a diamond begins with the 4Cs, but confident selection also requires proportion, symmetry, polish, certification and viewing the individual stone.
Cut & proportion
Precision of cut determines how a diamond returns light.
More than any other characteristics, the precision of cut and overall proportion of a diamond when being cut from a rough diamond ultimately determines the brilliance of the diamond.
The proportion of each individual diamond directly affects its brilliance and appeal. Diamonds with excellent proportions, symmetry and polish optimise their interaction with light. Often diamonds are cut to retain weight rather than excellent proportion, as this may sometimes yield a slightly higher price at the expense of quality.
Our standard ensures certified diamonds are accurately categorised according to their proportions, symmetry and polish, which ultimately determine their brilliance.
Colour
Small colour differences can have a significant effect on value.
The colour of a diamond is an important characteristic when determining a diamond’s value. Generally, the less colour, the higher the value. The exception is fancy-colour diamonds such as pinks and blues, which lie outside this colour range.
The untrained eye is incapable of making assessments that can dramatically affect a diamond’s value.
Carat weight
Carat describes weight, not the complete beauty or value of a diamond.
The weight of a diamond is measured in carats.
Carat weight alone does not determine a diamond’s value. Diamonds of equal weight can vary widely in price because of differences in cut, proportion, colour, clarity and other characteristics. Two diamonds that weigh the same can have completely different measurements.
Clarity
Every natural diamond carries its own internal fingerprint.
Because diamonds are formed deep within the earth’s core under extreme heat and pressure, they often contain unique birthmarks—either internal inclusions or external blemishes.
Virtually all diamonds have naturally occurring inclusions or blemishes. Their size, position and type directly affect a diamond’s beauty and value.
Two diamonds with the same clarity grade on a certificate can appear very different in person. Certified characteristics should be interpreted alongside an individual assessment.
Lab-grown diamonds
Created with the same crystal structure and optical properties as mined diamonds.
Laboratory-grown diamonds, also referred to as man-made, created or synthetic diamonds, are manufactured in a laboratory rather than formed naturally within the earth.
They are grown in highly controlled environments using advanced technological processes that duplicate the conditions under which diamonds naturally develop beneath the earth’s crust. They consist of carbon atoms arranged in the characteristic diamond crystal structure and exhibit the same optical and chemical properties.
Mining Free
Lab-grown diamonds are a responsible choice because no diamond mining is required.
Beauty & Quality
They have the same physical, chemical and optical properties as mined diamonds.
Value
They can offer excellent value compared with natural diamonds of comparable size and quality.
Diamond shapes
Top 10 most popular diamond shapes.
Diamond shape influences style, apparent size, light return and how a stone complements a setting. From the classic round to the elegant emerald and playful heart, compare the most recognised shapes before selecting.
1. Round Diamonds
Origin: The modern-day round brilliant was developed through Marcel Tolkowsky’s 1919 mathematical work on diamond proportions. Its 58 facets are arranged to return light with exceptional brilliance.
Benefits: Round is the classic benchmark and represents a large share of diamonds sold. Its primary advantage is maximum brilliance and sparkle.
Notable example: Mila Kunis received a round Tiffany & Co. engagement ring from Ashton Kutcher.
2. Princess Diamonds
Origin: The princess shape was developed in 1979 by Betzalel Ambar and Israel Itzkowitz to combine square geometry with brilliant-style light performance.
Benefits: Its clean edges and modern design make it the most brilliant of the widely recognised square shapes. With up to 76 facets, it can also disguise some inclusions.
Notable example: Nicole “Snooki” Polizzi wears a princess-cut engagement ring with pavé diamonds.
3. Cushion Diamonds
Origin: Cushion cuts evolved from old-mine cuts—square stones with rounded corners that date to the 1700s. Modern cushions use improved facet patterns for stronger light distribution.
Benefits: The soft square outline gives a romantic pillow-like appearance. Rounded corners are less prone to snagging and chipping than sharp-cornered shapes.
Notable example: Kim Kardashian previously wore a significant cushion-cut engagement ring.
4. Oval Diamonds
Origin: The modern oval brilliant was developed in 1957 by Lazare Kaplan, who became known for turning difficult rough into beautiful finished diamonds.
Benefits: Oval diamonds offer strong brilliance and often appear larger than round diamonds of the same carat weight. Their elongated outline can visually lengthen the finger.
Notable example: Blake Lively wears an oval centre diamond on a rose-gold pavé band.
5. Emerald Diamonds
Origin: Emerald-style step cuts trace back to table cuts of the 1500s. The name became established in the 1920s as the clean geometry suited Art Deco design.
Benefits: Broad step facets create a hall-of-mirrors effect rather than brilliant sparkle. The elongated outline is elegant and can have a slimming effect on the finger.
Notable example: Mariah Carey previously owned a substantial emerald-cut engagement ring.
6. Radiant Diamonds
Origin: Henry Grossbard developed the radiant cut in 1977 to combine the symmetry of an emerald shape with the sparkle of a brilliant cut.
Benefits: Radiants may be square or rectangular and commonly use 70 facets for strong light dispersion. Trimmed corners improve durability and reduce snagging.
Notable example: Anna Kournikova has worn a fancy-yellow radiant diamond ring.
7. Pear Diamonds
Origin: The pear form dates to the mid-1400s and is linked to Flemish diamond cutter Lodewyk van Bercken following the development of the polishing wheel.
Benefits: Also called a teardrop, it combines a rounded end with a pointed tip. It offers a distinctive silhouette and allows the wearer to choose the direction of the point.
Notable example: Paris Hilton previously wore a significant pear-shaped engagement ring.
8. Asscher Diamonds
Origin: The Asscher shape was created in 1902 by the Royal Asscher Diamond Company and refined in 1999 through the Royal Asscher variation.
Benefits: Its geometric step facets create a mirror-like effect associated with Art Deco design. Traditional and Royal Asscher variations use different facet structures.
Notable example: Elizabeth Taylor owned the celebrated 33.19-carat Krupp/Elizabeth Taylor Diamond.
9. Marquise Diamonds
Origin: The marquise shape is traditionally associated with an 18th-century commission by King Louis XV, inspired by the lips of the Marquise de Pompadour.
Benefits: Also called a navette or little boat, its elongated outline can appear larger than a round of equal weight and visually lengthen the finger.
Notable example: Catherine Zeta-Jones wears a marquise diamond in an east–west setting.
10. Heart Diamonds
Origin: The heart shape has been referenced since the 15th century as a symbol of love and royalty.
Benefits: It is one of the most difficult shapes to cut well because exact symmetry is essential. Stones of at least around half a carat generally show the outline more clearly.
Notable example: Lady Gaga previously received a heart-shaped engagement ring.