Charles Rose

You can be confident that Charles Rose provide only the finest high-quality diamonds from which to choose, upholding the ethos of quality, beauty and timelessness in every jewellery design. Our diamond grading guide below can help you select your perfect diamond.

DIAMOND GRADING

A universal grading standard helps assess a diamond's quality using the four C's: Cut, Colour, Clarity and Carat. Together, the four C's contribute to a diamond's beauty, but diamantaires agree that a high-quality cut is of utmost importance.

Cut

Cut refers to proportion, symmetry and polish – factors which affect how light reflects (brilliance), disperses (fire) and flashes (scintillation) off a diamond surface. The following grades are used to assess cuts:

  • Top grades: "Triple Excellent (Xc, Xc, Xc)" and "Ideal".
  • Average grades: VG (Very Good) and G (Good).

Colour

Shade refers to a diamond's colour, which can range from rare pure white to fancy coloured vivid shades like yellow, pink and green, although most tend to yellow/brown. There are four primary shades (Yellow, Dark Tinge, Brown and Dark Brown) further classified for intensity. The lack of colour in a diamond determines its grading, with higher colour grades assigned to diamonds with less colour. This is because colourless diamonds exhibit greater sparkle than yellowish/brownish tinted diamonds.

Diamond grades are standardised on a D–Z colour grading scale. Colourless diamonds graded D, E and F are the most expensive. The white (non-fancy colour) grades are Exceptional White Plus (D), Exceptional White (E), Rare White Plus (F), Rare White (G) and White (H), with tints ranging from I, J, K… to X, Y, Z. There are also several top grades for colour diamonds: Vivid, Fancy Intense, Fancy and Light fancy. Fancy colour diamonds are often more valuable than high-grade white diamonds.

Clarity

Clarity refers to inclusions, which are small, naturally occuring marks, fissures or foreign crystals in the diamond. Every diamond has billions of inclusions. However, many inclusions are not visible to the naked eye, so the diamond is “eye clean” (SI grade to VVS1). Flawless diamonds are “Loupe Clean”, meaning that inclusions are invisible even when using a 10x magnification lens.

There are several clarity grades: FL (internally and externally flawless – without surface blemishes), IF (internally flawless), VVSvs (1/2), VSs (1/2), SI (1/2) and Pk (1/2/3).

Numerous tiny inclusions can form milky white or grey “clouds” in a gem. Milkiness is also graded on the following scale: VSL (very slight), SL (slight), CVSL (centre very slight), CSL (centre slight), MED (medium) and Heavy.

Fluorescence

Diamond fluorescence refers to the phosphorescent after-glow that occurs when exposing the diamond to ultraviolet light, including sunlight. Fluorescence can be Nil, Faint, Medium, Strong or Very Strong. Faint fluorescence can brighten and whiten a gem’s appearance without affecting brilliance and can enhance fancy coloured stone hues further. However, strong fluorescence can look cloudy or impart a yellow/orange hue to a white diamond, making it appear of a lower colour grade.

Shape

Diamond cutters cut diamonds into a variety of shapes. Some traditional shapes were fashioned hundreds of years ago and exude a timeless aesthetic and old-world charm (such as emerald and cushion shapes). Others reflect elegant contemporary styles popularised within the last 20 years (for example, Asscher and princess shapes).

A classic round brilliant diamond is the most enduringly popular shape due to its exceptional radiance, brilliance and sparkle. Other highly favoured styles include alluring square and rectangular shapes.

Superb crafting enables the beauty of a diamond to be enhanced – the jewellery artisans at Charles Rose expertly shape the finest of diamonds into exquisite styles that captivate and dazzle with their transcendent beauty and sparkle.

Carat Weight

Carat weight measures a diamond’s weight, not size. The weight of a diamond is expressed in “points” up to 99 points (for example, 25 points refers to a 0.25 weight), with 100 points equal to 1 carat. Jewellers express diamond weights equal to or heavier than 1 carat in carats and decimals (for example, 1.25 carat).Many people mistakenly believe that a larger carat weight is preferable to a smaller carat weight. However, carat weight does not affect sparkle – brilliance and sparkle relate to a diamond’s cut. For example, a well-cut .98 carat diamond may appear larger and more sparkly than a poorly cut 1-carat weight diamond.

Nevertheless, carat weight has a significant impact on price, so it is an important consideration when selecting your perfect diamond.

"Ideal" or "Triple Excellent" cut diamonds have the best dimensions (proportion, symmetry and polish). View our carat weight chart to find out more about ideal cut gems. If you print the chart without rescaling, it will accurately print the true physical sizes of different carat weights for different diamond shapes. Keep in mind that some diamond shapes may appear larger than their actual carat weight. Also, diamonds can appear larger in certain ring settings, such as halo settings.

Remember, this chart is a guide only – the best way to select your perfect diamond is to consult with the skilled jewellers and consultants at Charles Rose. Our expert team are always available to assist you with your diamond selection.