A guide to a diamond’s quality

A diamond’s carat, colour, clarity and cut determine it’s value and beauty. The 4 C’s are a universal method for assessing the quality of diamonds and give dealers and customers the necessary know-how they need when buying diamonds.


The diamond’s weight and overall size determine the carat. Often the price of diamonds increases parallel to the carat weight. A grand diamond might highlight it’s other three C’s, but also potential flaws. Don’t let the size of a diamond be your only criteria: small diamonds can be just as precious, especially as an expression of genuine love.

The carat weight may not accurately reflect a diamond’s size, therefore it’s important to also pay attention to the distance across the top of the diamond and the cut grade. A perfectly cut diamond reflects the light out of the top, which makes it look bigger.

The ideal carat weight for a diamond ring depends on three factors:

  • The size of your/her finger. Naturally the smaller the finger, the larger the diamond looks. Don’t worry a large stone on a small and elegant hand might look out of balance. With the perfect setting we create a perfect harmony.
  • The ring setting defines the look and presents the diamond. A classic is the Prong setting, whereby prongs or claws hold the diamond. Simple, yet powerful. Or maybe the Channel, Bezel, Tension, Pavé or Bar setting suits you more. There is a setting for every personality.
  • Keep to your set budget. A jewel made of a fine selection of smaller diamonds can be just as beautiful as one large diamond ring.

White diamonds come in different shades from perfectly colourless to warm white. The value of a white diamond is determined by the lack of colour, while with fancy coloured diamonds it’s the opposite. The most common colour is yellow and the most rare – and therefore most expensive – are blue and pink.

Bright White

The white diamond’s GIA’s colour-grading scale is based on the absence of colour: the less colour, the higher the grade and value of the diamond. Diamonds are assigned a letter grade based on the amount of yellow present in the diamond. Diamonds with grade J or better are near colourless or actual colourless. The yellow tints are due to impurities, caused during the formation.

Fancy coloured

The value of a fancy coloured diamond is determined by the rarity and saturation or depth of the colour. A fancy yellow diamond is the most common coloured diamond, while a blue, green or pink one is rare. Grading coloured diamonds is more difficult than white diamonds, as each colour may have different levels of saturation. A Diamond Trading takes great care in selecting only the highest quality in fancy coloured diamonds.

Both bright white and fancy coloured diamonds might show a dash of brown or grey. This is not visible to the eye, yet it influences price and sparkling. A Diamond Trading pays great attention to these little details.

Diamond Colour
Z-NNoticeable colour. Not carried by A Diamond Trading.
M-KNoticeable colour.
J-INear-colourless. An exceptional value with slightly detectable warmth or tone.
H-GNear-colourless. Colour difficult to detect unless compared side-by-side against diamonds of better grades. A diamond of excellent value.
F-EColourless. Microscopic traces of colour can be detected by an expert gemologist. A rare diamond.
DAbslutely colourless. The highest colour grade. An extremely rare diamond.

Nearly every diamond has microscopic natural imperfections. When they blend into the diamond’s colour they have a lower impact on the diamond’s appearance.

The variety of imperfections is subdivided in different levels from flawless (FL), internally flawless (IF), very very slightly included (VVS1 & VVS2), very slightly included (VS1 & VS2), slightly included (SI1 & SI2) to included (I1, I2 & I3). Flawless or internally flawless diamonds are extremely rare and therefore come with a much higher cost. A Diamond Trading only offers diamonds with an included level of I2 or I3, which are the most imperfect diamonds, on demand.


Of the four C’s, the cut contributes the most to a diamond’s beauty and brilliance. A diamond’s cut is pure craftsmanship and requires thorough training and patience; it’s not an essential quality of the stone itself. The cut has three effects on appearance: brilliance, fire and scintillation.

The objectively measured light performance determines the cut grade of a diamond:

  • Brilliance: the brightness created when white light reflects out of the top of a perfectly cut diamond. A diamond cut too shallow or too deep is less bright as the light flows out of the bottom or sides and doesn’t return to the eye.
  • Fire: the colourful sparkle showing when the diamond is exposed to light. When the light enters the diamond it is broken down into different colours.
  • Scintillation: the flashes of light when you move the diamond in your hand. The sparkles across the surface show best in floodlight.

In our collection we have diamonds with a ‘hearts and arrows’ pattern. When viewed from the top the diamond shows eight symmetrical arrows, and from pavilion view eight symmetrical hearts. A perfect ‘hearts and arrows’ pattern requires the highest level of cutting precision and sparkles like no other. Subtle details in shape, spacing and position also determine the value and are often only detectable by experienced professionals.

Do you have questions or are you looking for personal guidance?

We are happy to share our knowledge and expertise with you.