Choosing a diamond: The Four C’s

The 4 C’s are four variables that are used to calculate the quality and value of a diamond. Both rough and cut diamonds are separated and graded based on these four characteristics. As a consumer, your first step in shopping for a diamond should be to learn and understand the "4 C's" diamond grading system.

Cut

Of the 4Cs, a diamond's cut has the greatest influence on its fire, sparkle and brilliance. Cut not only refers to shape of a diamond,, but more importantly to its proportions (how the diamond's angles and facets relate to one another), symmetry (the precision of its cut) and polish (the condition of your diamond's surface). In a well-proportioned and symmetrical diamond, light will enter and exit through the crown to the eye. A poorly cut diamond, however, allows too much light to escape through the sides and bottom. As a result, a diamond with a poor cut will appear dull, even if it has good colour and clarity.



Different shapes of diamonds

The cut of a diamond may vary and the following are the most common of the fancy cut diamonds:

Emerald Marquise Oval Pear
 
Radiant Heart Princess  

Colour

Colour is one of the 4 C's which determine the price of a diamond. De Beers make diamond promotional material available to every jeweller in the form of leaflets, showcards and more, and yet there is still much confusion about the role of colour as a quality factor in diamonds.

Colour Grading

In recent years, a de-facto international standard grading system has evolved, based on the standards of the G.I.A., the Gemmological Institute of America. Terminology differs in European standards, but the grades are identical. The following table shows the GIA, traditional UK, and CIBJO colour scales, together with our graphical representation. We have assumed that your computers video card can display at least 256 shades of colour. Obviously this chart may appear different on different monitors, therefore it is advisable to treat our colour column in the table as only a general guide rather than as an exact rendition of any particular colour.

Are Diamonds White?

It is commonly believed that most diamonds are white, although strictly we should say colourless. This is incorrect, most diamonds actually show at least a trace of body colour, and many are quite deeply coloured. To their credit, De Beers do point out that most diamonds are faintly yellow, however many diamonds are faintly brown, green, grey, or other colours.

Is White Best?

It's really a matter of personal preference. Because De Beers promote white as being the most expensive colour for diamonds, most people blindly believe that white is best, and some even believe that yellow is bad! While it is generally true that colourless diamonds are more expensive than tinted diamonds, it is not true that they are better, just that there is a difference. Many distinctly yellow diamonds are very bright, sparkling, attractive and desirable.

What About Fancy Colours?

Intensely coloured diamonds are very rare, and are also very attractive and desirable. Because they are not actively marketed, certainly not by De Beers, knowledge levels and demand for them is relatively low. Even so, they command high prices, often much more than colourless diamonds. These intensely coloured diamonds are known as "Fancy" coloured or "Fancies". They exist in yellow, greens, brown, red, orange, blue, and other colours. Also some diamonds with faint or pale colouring are rare and desirable, these colours include pink and blue. It is our own opinion that the main reason De Beers do not promote colour as a positive attribute in diamonds is that most diamonds are near colourless, and fancy colours are so very rare. Promotion of colour would risk educating consumers to appreciate coloured stones, and this may divert demand away from diamonds, and in the direction of ruby, sapphire, emerald, amethyst, opals, and other naturally coloured gemstones. Some coloured diamonds can be treated by irradiation and heat to change or intensify their colour. These are termed as treated fancies, and can be bought for lower prices than natural fancies. Naturally we have a page about coloured diamonds.

What About Fire

The ability of a diamond to refract and disperse white light into all the rainbow colours of the spectrum is sometimes called "fire", and it is one of the desirable qualities of diamonds. Well polished diamonds sparkle and flash with lots of fire. It is easy to confuse this aspect of colour with the "body" colour of a diamond. So what do we mean by "body" colour?

What Is "Body" Colour"

Body colour is simply the colour seen when white light travels through the diamond without being dispersed, rather than the multi-coloured flashes caused by dispersion. Body colour is best judged by viewing the stone through the side rather than through the top. It is the colour which the diamond would appear if it were not facetted, and is the stone's true colour. The "fire" actually confuses the eye, and makes it almost impossible to judge the body colour. The term "body colour" is only used to emphasize which aspect of colour is intended, when the word colour is used, it normally is understood to mean body colour.

Clarity

Almost all diamonds contain minute mineral traces called inclusions. Most are not visible to the naked eye and require magnification to become apparent. The fewer the number of inclusions or imperfections, the more rare and hence valuable the stone will be. Clarity is the term used to indicate the extent to which the diamond you purchase is free of these inclusions. Flaws and inclusions give each diamond its unique fingerprint that makes every diamond different.

Carat - Weight

The word "carat" is taken from the carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them. "One carat is divided into 100 "points", so that a diamond of 25 points is described as a quarter of a carat or 0.25 carats. One carat is the equivalent of 0.2 grams. Larger diamonds are uncovered less often than smaller ones. Thus, large diamonds are rare and have a greater value per carat. For that reason, the price of a diamond rises exponentionaly to its size. For example if you had two identical diamonds i.e. same colour, clarity and cut but the one weighs 1 carat and the other only half a carat, the 1 carat diamond may be worth as much as 350% more than the half carat! It is true that the larger the diamond, the more rare it is. However, two diamonds of equal size can have very different values, depending on their quality i.e. the other three C's.