The 4Cs are a series of characteristics or parameters conferring a value to the diamond. If there wasn’t this method, it would be impossibile to distinguish each diamond from another. The first to introduce the grading of the 4cs was the G.I.A. (Geomological Institute of America). These parameters are:

  • Carat;
  • Color;
  • Clarity;
  • Cut;
  • Fluorescence (considered the 5th C).


The carat is the unity of mass for diamond and is equal to 0,20 grams (1 carat = 0,20 grams). Below one carat, there are hundredths or most commonly “points”. A 0,50 ct diamond is equivalent to 50 hundredths or 50 points. The word carat comes from the carob seeds used to weigh stones in the past. The diamond weight determines its size and its diameter.



The colour is a very important characteristic for a diamond and it is also the main element that influences our appreciation of a gem, especially when mounted on a jewel. Gems with no color and transparent, the purest ones, are called “colorless”, followed by the “near colourless” and by the coloured ones called “slightly tinted”. The certificate classifies all diamonds, even those of yellow colour with a low saturation, as diamonds according to the normal colour grading and follows the scale from D (exceptional white) to Z (pale yellow).



Total “pure” diamonds are extremely rare naturally. A diamond may hide some crystallizations inside, known as inclusions. During the clarity test of a diamond, it is necessary to evaluate the number of the inclusions, their nature and position. The inclusions can be formed when the diamond comes into contact with other substances or when goes through variations of temeperature or pressure, during its growing in the Earth’s crust. The inclusions have been classified as: “FL-IF”, “VVS”, “VS”, “SI” and “I”.

  • IF (internal flawless): This category indicates that the stone has no inclusions;
  • VVS (Very Very Small Inclusion): In this case, the stone presents very very small inclusions that can barely be seen under a magnifying glass x10;
  • VS (Very Small Inclusion): In this case, the stone presents very small inclusions that can unlikely be seen under a magnifying glass x10;
  • SI (Small Inclusion): This is a lower category because the inclusions can be easily seen under a magnifying glass x10;
  • I (Included): Included 1- The inclusions will be visible to the naked eye. Included 2 – There will be many and big inclusions, clearly visible to the naked eye. Included 3 – There will be many and big inclusions that seriously affect the brightness of the stone.


The cut can be described as the man’s contibution to the beauty of a diamond. It affects the other qualities we have seen so far, for example, highlighting the color or hiding some inclusions. The ideal proportions give the best brilliance and brightness to the stone. They do not refer to the diamond size, but to the way the stone is cut. It is the cut that gives brilliance to diamond. The facets have to be perfectly proportioned, a brilliant cut diamond must have 57 facets.



Fluorescence is the sparlke, usually bluish, which is released from some diamonds when exposed to the ultraviolet light. The best diamonds don’t have fluorescence. Generally, a weak fluorescence doesn’t influence the look of the diamond. Some clients prefer stones of weak or moderate blue fluorescence because a yellowish diamond (less priced) can appear whiter in daylight.

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