The basics of the Diamond 4Cs


Every diamond is characterised by the famous 4Cs: Carat, Clarity, Colour and Cut. The diamond clarity, diamond colour and diamond cut (proportions) are the quality elements which together with the diamond carat (weight) determine the value of a stone. The higher a diamond grades in any of these elements, the rarer and the higher its financial value will be. Each of the 4Cs is equally important and plays a vital role in the appearance of a diamond. Every diamond certificate or grading report will state the grade of each of the diamond 4Cs.


Diamond carat (weight)

The diamond carat is the unit of weight for all gemstones. One carat, which has a total weight of only 0.20 grams, is subdivided into 100 "points". Therefore a diamond measuring 75 points is ¾ carat in weight, or 0.75ct.


Diamond clarity

Diamond clarity scale
The clarity of a diamond is determined by the number, nature, position, size and colour of internal characteristics called "inclusions" and surface features called "blemishes". These irregularities occur during the formation of the diamond.

Diamonds are mostly pure carbon, however, during crystallization other minerals nearby, or even other bits of carbon forming more quickly may become trapped within the mass. These show themselves as the various characteristics which make up the clarity of a diamond (included crystals, feathers, clouds etc).

The diamond clarity is measured on a scale ranging from pure (Internally Flawless - IF) to heavily included (I3). The clarity of a diamond is graded by using 10X magnification under good lighting by an experienced grader. The final clarity grade is determined by how easy the inclusions and blemishes are for the grader to see.

At Congenial Diamonds, we offer diamonds with eye-clean clarity varying from IF to SI2:

Diamond bulletInternally Flawless (IF) or Loupe Clean (LC) – No inclusions visible to a skilled diamond grader using 10X magnification.

Diamond bulletVery, Very Small Inclusion (VVS1 and VVS2) – Inclusions that are difficult for a skilled grader to see under 10X magnification.

Diamond bulletVery Small Inclusion (VS1 and VS2) – Inclusions that are clearly visible to a skilled grader using 10X magnification.

Diamond bulletSmall Inclusion (SI1 and SI2) – Inclusions that are noticeable to a skilled grader using 10X magnification.


Diamond colour

GIA Diamond colour scale
Ideally, a diamond should have no colour at all (colourless), like a drop of spring water. Increasing degrees of body colour are measured on a scale ranging from no colour at all (D) to yellow (Z). Beyond "Z" is the range where the diamond's colour is vivid and rich, called "fancy colours", which are very highly priced due to their rarity. Diamond colour grading is done by comparing the diamond under study against a set of diamonds of known colour called "master stones" under either artificial or natural daylight.

The range of diamond colour offered in our jewellery ranges from D to I.


Diamond cut

Diamond cut

Sometimes the forgotten "C", the diamond cut ensures that a given stone has maximum brilliance and sparkle intensity. This would not be the case were the stone cut to yield maximum weight alone. The right proportions of the diamond cutting process are what brings out the fire in a diamond. Hence the diamond cut has a profound effect on the visual appearance of the stone.

The cut of a diamond is graded by experts in gemological laboratories. The range of grading and certification starts from Excellent, Very Good, Good and Fair. Excellent grade is awarded to diamonds with the highest level of brilliance, while Fair implies poorer light reflection and less sparkle.
The diamond cut can also affect the visual size of a stone. Two diamonds of the same carat (weight) can appear to be different in size depending on the cut.


Fancy shape diamonds

The diamond cut at its most basic level also refers to the shape of a diamond. Note that the shape does not affect the quality of the stone. The shape is often dictated by the shape of the rough diamond; each rough diamond is cut to the shape which provides the highest yield.

At Congenial Diamonds we offer diamond jewellery set with various shapes to suit individual preferences:

  • Round brilliant cut

    Round brilliant cut

    Classic, versatile and with more fire and brilliance than any of the other shapes, making it the most popular of the shapes.

  • Princess cut

    Princess cut

    True to its name, the Princess cut is elegant and chic with a contemporary look due to its square shape and sharp corners.

  • Pear shape

    Pear shape

    A unique and feminine shape, with a rounded edge and a pointed end, giving a delicate and stunning look.

  • Emerald cut

    Emerald cut

    One of the first shapes to be used in jewellery design, hence its vintage look and timeless elegance. Also known as “step cut” due to its broad facets that highlight the clarity of the diamond.

  • Marquise shape

    Marquise shape

    One of the more unusual shapes but equally stunning. It combines the elongated shape of the oval with pointed edges at opposite sides of the stone. It maximises the top look for the carat.

  • Cushion cut

    Cushion cut

    A rectangular shape diamond with rounded corners and slightly rounded sides. It boasts of large facets which maximise the top look for the carat. A less popular choice in Europe compared to the US.

  • Oval cut

    Oval cut

    A rarer and more elongated for of the round brilliant cut diamond.

  • Heart shape

    Heart shape

    A romantic and symbolic choice. One of the rarer shapes.