Carat
One carat equals 1/5 of a gram (i.e. 1ct = 0.2 gr).
Diamonds, as every other precious stone, weighs in carats with two decimal digits’ precision (electronic scales today have a precision of three decimal digits).
It is impressive that carob cores have almost the same weight (0,2 grams) and this is the reason that in the past this was the measurement unit. The word "carat" derived from those little seeds (the word "kirat" actually means "seed" in Arab) so this is the known weight measure unit of the precious stones. According to others, the word "kirat" comes from other words of the carob itself.
Colour
A diamond's colour grade actually refers to the lack of colour. In other words, diamonds that are white, and contain little or no colour, receive higher quality grades than those, with visible colour.
In order to evaluate a diamond's color, it is compared with standard diamonds complexions and is classified accordingly. There are several methods of complexion classes which have changed over time. The most common international systems are two: the GIA and the CIBJO systems.
Clarity
The term "Clarity" is not very cadet because no diamond is actually 'dirty’ !
However, during the diamond development inside the Earth's crust and under certain temperature and pressure conditions (there is heterogeneity in these depths) certain inclusions penetrate in the diamonds. These inclusions are nature's imprints and they are used to define each diamond's origin (and that's why every diamond is unique)!
Every natural diamond includes inclusions. The degree to which these inclusions (as position, quantity, features etc) reduce the optical specifications of the diamonds is decisive in their quality classification.
Diamond's qualitative classification (clarity) is made under 10X magnification, under specific light conditions and exclusively by certified Gemologists!
The most common international systems are two: the GIA and the CIBJO systems.
Cut
The Cut Grade defines a diamond's brilliance. In other words, the better a diamond is cut, the more it will shine!
The cut is the only of the four features of a diamond that depends exclusively on human factor. The best the ratios (%) and the cut symmetry, the better the result! With consistency to the internal reflection, the maximum possible brightness and the maximum possible light dissipation!
The Cut is evaluated as Very Good, Good, Fair, and Poor. So the Cut is the most important feature of a diamond and the most important process level of every precious stone because this step gives them their final form and highlights their beauty!
Certification
The diamond may be the ultimate symbol of love, but is also a timeless investment due to its rarity and value.
Therefore, you have to feel confident regarding the authenticity of the stone you own. For nearly a decade, the majority of customers address two sources, in order to assess the quality of gems: the appraiser and the jeweler, who sold them the precious stone.
These two, were often, especially some years ago, the same person. However, with the proliferation of specialized technologies and the continuous rise of a demanding market, many consumers now trust a more specific document that assesses the true value of precious stones, such as the Certificate of diamonds.